Display device for shovel, and shovel

ABSTRACT

A display device for a shovel displays a screen that includes an image represented by image data captured by an imaging device included in the shovel. The screen further includes an icon image corresponding to an instruction to correct a reference value used to calculate the weight of a load object conveyed by the end attachment of the shovel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application filed under 35 U.S.C.111(a) claiming benefit under 35 U.S.C. 120 and 365(c) of PCTInternational Application No. PCT/JP2022/013563, filed on Mar. 23, 2022and designating the U.S., which claims priority to Japanese PatentApplication No. 2021-055151, filed on Mar. 29, 2021. The entire contentsof the foregoing applications are incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to display devices for shovels and toshovels.

Description of Related Art

With respect to shovels, the technique of calculating the weight ofearth and sand or the like loaded in a bucket by comparing the weight ofthe bucket in an empty load state with the weight of the bucket afterexcavation is known.

SUMMARY

According to an aspect, a display device for a shovel displays a screenthat includes an image represented by image data captured by an imagingdevice included in the shovel. The screen further includes an icon imagecorresponding to an instruction to correct a reference value used tocalculate the weight of a load object conveyed by the end attachment ofthe shovel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a shovel according to an embodiment;

FIG. 2 is a diagram for schematically illustrating an example of aconfiguration of the shovel according to the embodiment;

FIG. 3 is a diagram for schematically illustrating an example of ahydraulic system configuration for the shovel according to theembodiment;

FIG. 4A is a diagram of a part of the hydraulic system related tooperation of an arm cylinder;

FIG. 4B is a diagram of a part of the hydraulic system related to a boomcylinder;

FIG. 4C is a diagram of a part of the hydraulic system related to abucket cylinder;

FIG. 4D is a diagram of a part of the hydraulic system related to aswing hydraulic motor;

FIG. 5 is a diagram for schematically illustrating an example ofcomponents related to an earth and sand weight detection function of theshovel according to the embodiment;

FIG. 6 is a diagram for explaining a reference value;

FIG. 7 is a flowchart for explaining processing performed by a displaycontrol part;

FIG. 8 is a diagram for illustrating an example of a main screen; and

FIG. 9 is a diagram for illustrating an example of a loading workscreen.

DETAILED DESCRIPTION

The related-art technique described above is silent with respect to amethod of setting the weight of the bucket in the empty load state to besubtracted from the weight of the bucket after excavation.

According to an embodiment, the weight of an end attachment in the emptyload state can be easily set.

An embodiment is described below with reference to the accompanyingdrawings.

First, an overview of a shovel 100 according to the embodiment is givenwith reference to FIG. 1 . FIG. 1 is a side view of the shovel 100serving as an excavator according to this embodiment.

In FIG. 1 , in the shovel 100, an example of a target track BS describedbelow is also illustrated on an upward inclined surface ES to beexcavated.

The shovel 100 according to this embodiment includes a lower travelingbody 1, and an upper swing body 3 which is swingable mounted on thelower traveling body 1 via a swing mechanism 2. The shovel furtherincludes a boom 4, an arm 5, and a bucket 6 which constitutes anattachment, and a cabin 10.

The lower traveling body 1 causes the shovel 100 to travel by the pairof left and right crawlers being hydraulically driven by travelinghydraulic motors 1L, 1R (described below, see FIG. 2 ), respectively.That is, the pair of traveling hydraulic motors 1L, 1R (an example of atraveling motor) drives the lower traveling body 1 (crawlers) as adriven part.

The upper swing body 3 is driven by a swing hydraulic motor 2A(described below, see FIG. 2 ) to swing with respect to the lowertraveling body 1. That is, the swing hydraulic motor 2A is a swingdriving part that drives the upper swing body 3 as a driven part, andcan change the orientation of the upper swing body 3.

The upper swing body 3 may be electrically driven by a motor(hereinafter referred to as a “swing motor”) instead of the swinghydraulic motor 2A. That is, similarly to the swing hydraulic motor 2A,the swing motor is a swing drive part that drives the upper swing body 3as a driven part, and can change the orientation of the upper swing body3.

The boom 4 is pivotally attached to the front center portion of theupper swing body 3 to be able to move vertically, the arm 5 is pivotallyattached to the distal end portion of the boom 4 to be able to pivotvertically, and the bucket 6 serving as an end attachment is pivotallyattached to the distal end portion of the arm 5 to be able to pivotvertically. The boom 4, the arm 5, and the bucket 6 are hydraulicallydriven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9,respectively, serving as hydraulic actuators.

Note that the bucket 6 is an example of an end attachment, and anotherend attachment such as a slope finishing bucket, a dredging bucket, or abreaker may be attached to the distal end portion of the arm 5 insteadof the bucket 6 depending on the work content or the like.

The cabin 10 is an operation room in which the operator rides, and ismounted on the front left side of the upper swing body 3.

Next, a specific configuration of the shovel 100 according to thisembodiment will be described with reference to FIG. 2 .

FIG. 2 is a diagram for schematically illustrating an example of theconfiguration of the shovel 100 according to this embodiment.

In FIG. 2 , a path for a mechanical power system, a hydraulic oil line,a pilot line, and a path for an electric control system are indicated bya double line, a solid line, a dashed line, and a dotted line,respectively.

The drive system of the shovel 100 according to this embodiment includesan engine 11, a regulator 13, a main pump 14, and a control valve unit17. As described above, the hydraulic drive system of the shovel 100according to this embodiment also includes hydraulic actuators such asthe traveling hydraulic motors 1L, 1R, the swing hydraulic motor 2A, theboom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 thathydraulically drive the lower traveling body 1, the upper swing body 3,the boom 4, the arm 5, and the bucket 6, respectively.

The engine 11 is a main power source in the hydraulic drive system, andis mounted on the rear portion of the upper swing body 3, for example.Specifically, the engine 11 constantly rotates at a predetermined targetspeed under direct or indirect control of a controller 30 (control part)described below to drive the main pump 14 and a pilot pump 15. Theengine 11 is, for example, a diesel engine fueled with diesel fuel.

The regulator 13 controls the discharge amount of the main pump 14. Forexample, the regulator 13 adjusts an angle (tilt angle) of a swash plateof the main pump 14 in response to a control command from the controller30. The regulator 13 include, for example, regulators 13L, 13R as willbe described below.

The main pump 14 is mounted on, for example, the rear portion of theupper swing body 3 in the same manner as the engine 11, and supplieshydraulic oil to the control valve unit 17 through a high-pressurehydraulic line. As described above, the main pump 14 is driven by theengine 11. The main pump 14 is, for example, a variable displacementhydraulic pump, and as described above, under the control of thecontroller 30, the regulator 13 adjusts the tilt angle of the swashplate, thereby adjusting the stroke length of the piston and controllingthe discharge flow rate (discharge pressure). The main pump 14 includes,for example, main pumps 14L, 14R as will be described below.

The control valve unit 17 is, for example, a hydraulic control devicethat is mounted in the central portion of the upper swing body 3 andcontrols the hydraulic drive system according to an operation performedon an operation device 26 by the operator. As described above, thecontrol valve unit 17 is connected to the main pump 14 via thehigh-pressure hydraulic line, and selectively supplies the hydraulic oilsupplied from the main pump 14 to the hydraulic actuators (the travelinghydraulic motors 1L, 1R, the swing hydraulic motor 2A, the boom cylinder7, the arm cylinder 8, and the bucket cylinder 9) according to theoperation state of the operation device 26.

Specifically, the control valve unit 17 includes control valves 171 to176 that each controls the flow rate and the flow direction of thehydraulic oil supplied from the main pump 14 to the respective hydraulicactuators. More specifically, the control valve 171 corresponds to thetraveling hydraulic motor 1L, the control valve 172 corresponds to thetraveling hydraulic motor 1R, and the control valve 173 corresponds tothe swing hydraulic motor 2A.

Furthermore, the control valve 174 corresponds to the bucket cylinder 9,the control valve 175 corresponds to the boom cylinder 7, and thecontrol valve 176 corresponds to the arm cylinder 8. The control valve175 includes, for example, control valves 175L, 175R as will bedescribed below, and the control valve 176 includes, for example,control valves 176L, 176R as will be described below. Details of thecontrol valves 171 to 176 will be described below.

The operation system of the shovel 100 according to this embodimentincludes the pilot pump 15 and the operation device 26. The operationsystem of the shovel 100 also includes a shuttle valve 32 for aconfiguration related to a machine control function by the controller 30described below.

The pilot pump 15 is mounted on the rear portion of the upper swing body3, for example, and supplies a pilot pressure to the operation device 26via a pilot line. The pilot pump 15 is, for example, a fixeddisplacement hydraulic pump, and is driven by the engine 11 as describedabove.

The operation device 26 is provided in the vicinity of the operator'sseat in the cabin 10, and is an operation input device for an operatorto operate various operation elements (the lower traveling body 1, theupper swing body 3, the boom 4, the arm 5, the bucket 6, and the like).

In other words, the operation device 26 is operation input device forthe operator to operate the hydraulic actuators (that is, the travelinghydraulic motors 1L, 1R, the swing hydraulic motor 2A, the boom cylinder7, the arm cylinder 8, the bucket cylinder 9, and the like) that drivethe respective operating elements.

The operation device 26 is connected to the control valve unit 17directly through a pilot line on the secondary side thereof orindirectly through the shuttle valve 32 described below provided in thepilot line on the secondary side. Thus, a pilot pressure correspondingto the operation states of the lower traveling body 1, the upper swingbody 3, the boom 4, the arm 5, the bucket 6, and the like in theoperation device 26 can be input to the control valve unit 17.

The control valve unit 17 can therefore drive each hydraulic actuatoraccording to the operation states of the driven parts of the operationdevice 26. The operation device 26 includes, for example, a lever devicethat operates the arm 5 (arm cylinder 8). The operation device 26 alsoincludes, for example, lever devices 26A to 26C that operate the boom 4(boom cylinder 7), the bucket 6 (bucket cylinder 9), and the upper swingbody 3 (swing hydraulic motor 2A) (see FIG. 4 ). Furthermore, theoperation device 26 includes, for example, a lever device or a pedaldevice that operates each of the pair of left and right crawlers(traveling hydraulic motors 1L, 1R) of the lower traveling body 1.

The shuttle valve 32 has two inlet ports and one outlet port, andoutputs, from the outlet port, a hydraulic oil having the higher pilotpressure of the pilot pressures input to the two inlet ports. One of thetwo inlet ports of the shuttle valve 32 is connected to the operationdevice 26 and the other is connected to a proportional valve 31.

The outlet port of the shuttle valve 32 is connected to a pilot port ofthe corresponding control valve in the control valve unit 17 through thepilot line (see FIG. 4 for details). Therefore, the shuttle valve 32 canapply the higher pilot pressure between the pilot pressure generated bythe operation device 26 and the pilot pressure generated by theproportional valve 31 to the pilot port of the corresponding controlvalve.

That is, the controller 30 described below causes the proportional valve31 to output a pilot pressure higher than the secondary-side pilotpressure output from the operation device 26, thereby controlling thecorresponding control valve and controlling the operations of thevarious operating elements regardless of the operations of the operationdevice 26 by the operator. The shuttle valve 32 includes, for example,shuttle valves 32AL, 32AR, 32BL, 32BR, 32CL, 32CR, as will be describedbelow.

Note that the operation device 26 (a left operation lever, a rightoperation lever, a left traveling lever, and a right traveling lever)may not be a hydraulic pilot type that outputs a pilot pressure but maybe an electric type that outputs an electric signal.

In such a case, the electric signal from the operation device 26 isinput to the controller 30, and the controller 30 controls each of thecontrol valves 171 to 176 in the control valve unit 17 in accordancewith the input electric signal, thereby driving the respective varioushydraulic actuators according to the content of the operation withrespect to the operation device 26.

For example, the control valves 171 to 176 in the control valve unit 17may be solenoid type spool valves that are driven in response tocommands from the controller 30. Furthermore, for example, between thepilot pump 15 and the pilot port of each of the control valves 171 to176, a solenoid valve that operates in accordance with an electricsignal from the controller 30 may be disposed.

In such a case, when a manual operation using the electric operationdevice 26 is performed, the controller can operate each of the controlvalves 171 to 176 according to the content of the operation with respectto the operation device 26 by controlling the solenoid valve to increaseor decrease the pilot pressure by an electric signal corresponding tothe operation amount of the manual operation (for example, leveroperation amount).

The control system of the shovel 100 according to this embodimentincludes the controller 30, a discharge pressure sensor 28, an operationpressure sensor 29, the proportional valve 31, a display device 40, aninput device 42, a sound output device 43, a storage device 57, a boomangle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, avehicle body inclination sensor S4, a swing state sensor S5, an imagingdevice S6, a positioning device PS, and a communication device Tl.

The controller 30 (an example of the control device) is provided in thecabin 10, for example, and performs drive control with respect to theshovel 100. The functions of the controller 30 may be implemented by anygiven hardware, software, or any combination thereof. For example, thecontroller 30 is mainly constituted by a microcomputer including one ormore processors such as a central processing unit (CPU), a read onlymemory (ROM), a random access memory (RAM), a nonvolatile auxiliarystorage device, various input/output interface devices, and the like.The controller 30 performs various functions by, for example, executingvarious programs stored in the ROM or the nonvolatile auxiliary storagedevice by the CPU.

For example, the controller 30 sets a target rotation speed based on awork mode or the like set in advance by a predetermined operation of anoperator or the like, and performs drive control to rotate the engine 11at a constant speed.

The controller 30 also outputs, for example, a control command to theregulator 13 as necessary to change the discharge amount of the mainpump 14.

Furthermore, the controller 30 performs, for example, control related toa machine guidance function of guiding a manual operation of the shovel100 through the operation device 26 by an operator. The controller 30performs, for example, control related to a machine control function ofautomatically assisting a manual operation of the shovel 100 through theoperation device 26 by an operator.

That is, the controller 30 includes a machine guidance part 50 as afunctional part related to the machine guidance function and the machinecontrol function. The controller 30 includes an earth and sand weightprocessing part 60 described below.

Note that a part of the functions of the controller 30 may be performedby other controllers (control devices). That is, the functions of thecontroller 30 may be performed in a mode in which the functions aredistributed to the multiple controllers. For example, the machineguidance function and the machine control function may be performed by adedicated controller (control device).

The discharge pressure sensor 28 detects a discharge pressure of themain pump 14. A detection signal corresponding to the discharge pressuredetected by the discharge pressure sensor 28 is taken into thecontroller 30. The discharge pressure sensor 28 includes, for example,discharge pressure sensors 28L, 28R as will be described below.

As described above, the operation pressure sensor 29 detects the pilotpressure on the secondary side of the operation device 26, that is, thepilot pressure corresponding to the operation state (for example, theoperation content such as the operation direction and the operationamount) related to each operation element (that is, the hydraulicactuator) in the operation device 26.

A detection signal of the pilot pressure corresponding to the operationstates of the lower traveling body 1, the upper swing body 3, the boom4, the arm 5, the bucket 6, and the like in the operation device 26 bythe operation pressure sensor 29 is taken into the controller 30. Theoperation pressure sensor 29 includes, for example, operation pressuresensors 29A to 29C as will be described below.

Instead of the operation pressure sensor 29, other sensors capable ofdetecting operation states related to the respective operation elementsin the operation device 26, for example, encoders, potentiometers, orthe like capable of detecting operation amount (tilt amount) or tiltdirections of the lever devices 26A to 26C or the like may be provided.

The proportional valve 31 is provided in the pilot line connecting thepilot pump 15 and the shuttle valve 32, and is configured to be able tochange a flow path area (a cross-sectional area through which thehydraulic oil can flow) of the pilot line. The proportional valve 31operates in response to a control command input from the controller 30.

Thus, the controller 30 can supply the hydraulic oil discharged from thepilot pump 15 to the pilot port of the corresponding control valve inthe control valve unit 17 via the proportional valve 31 and the shuttlevalve 32, even when the operation device 26 (specifically, the leverdevices 26A to 26C) is not operated by the operator. The proportionalvalve 31 includes, for example, proportional valves 31AL, 31AR, 31BL,31BR, 31CL, and 31CR as will be described below.

The display device 40 is provided at a location that is easily visibleto the seated operator in the cabin and displays various informationimages under the control of the controller 30. The display device 40 maybe connected to the controller 30 via an in-vehicle communicationnetwork such as a controller area network (CAN), or may be connected tothe controller 30 via a one-to-one dedicated line.

The input device 42 is provided within reach of an operator seated inthe cabin 10, receives various operation inputs from the operator, andoutputs a signal corresponding to the operation input to the controller30. The input device 42 includes a touch panel mounted on a display ofthe display device 40 that displays various information images, a knobswitch provided at a tip of a lever portion of each of the lever devices26A to 26C, a button switch provided around the display device 40, alever, a toggle, a rotary dial, and the like. A signal corresponding tothe content of an operation on the input device 42 is taken into thecontroller 30.

The sound output device 43 is provided in, for example, the cabin 10,connected to the controller 30, and outputs sound under the control ofthe controller 30. The sound output device 43 is a speaker, a buzzer, orthe like, for example. The sound output device 43 outputs variousinformation by sound in response to a sound output command from thecontroller 30.

The storage device 57 is provided in the cabin 10, for example, andstores various information under the control of the controller 30. Thestorage device 57 is, for example, a nonvolatile storage medium such asa semiconductor memory. The storage device 57 may store informationoutput by various devices during the operations of the shovel 100 or maystore information acquired via various devices before the operations ofthe shovel 100 is started.

For example, the storage device 57 may store date related to the targetconstruction surface that is acquired via the communication device Ti orthe like or set through the input device 42 or the like. The targetconstruction surface may be set (stored) by an operator of the shovel100 or may be set by a construction manager or the like.

The boom angle sensor S1 is attached to the boom 4, and detects anelevation angle (hereinafter referred to as a “boom angle”) of the boom4 with respect to the upper swing body 3, for example, an angle formedby a straight line connecting supporting points at both ends of the boom4 with respect to a swing plane of the upper swing body 3 in a sideview. The boom angle sensor S1 may include, for example, a rotaryencoder, an accelerometer, a six-axis sensor, an inertial measurementunit (=), or the like.

The boom angle sensor S1 may include a potentiometer using a variableresistor, a stroke sensor that detects stroke amount of the hydrauliccylinder (boom cylinder 7) corresponding to boom angle, and the like.Hereinafter, the same applies to the arm angle sensor S2 and the bucketangle sensor S3. A detection signal corresponding to the boom angledetected by the boom angle sensor S1 is taken into the controller 30.

The arm angle sensor S2 is attached to the arm 5 and detects a rotationangle (hereinafter referred to as an “arm angle”) of the arm 5 withrespect to the boom 4, for example, an angle formed by a straight lineconnecting the supporting points at both ends of the arm 5 with respectto a straight line connecting the supporting points at both ends of theboom 4 in a side view. A detection signal corresponding to the arm angledetected by the arm angle sensor S2 is taken into the controller 30.

The bucket angle sensor S3 is attached to the bucket 6, and detects arotation angle (hereinafter, referred to as a “bucket angle”) of thebucket 6 with respect to the arm 5, for example, an angle formed by astraight line connecting a supporting point and a tip (cutting edge) ofthe bucket 6 with respect to a straight line connecting supportingpoints at both ends of the arm 5 in a side view. A detection signalcorresponding to the bucket angle detected by the bucket angle sensor S3is taken into the controller 30.

The vehicle body inclination sensor S4 detects an inclination state ofthe vehicle body (the upper swing body 3 or the lower traveling body 1)with respect to a horizontal plane. The vehicle body inclination sensorS4 is attached to the upper swing body 3, for example, and detectsinclination angles of the shovel 100 (that is, the upper swing body 3)about two axes in the front-rear direction and the left-right direction(hereinafter referred to as “front-rear inclination angle” and“left-right inclination angle”).

The vehicle body inclination sensor S4 may include, for example, arotary encoder, an accelerometer, a six-axis sensor, an IMU, or thelike. A set of detection signals corresponding to the inclination angles(front-rear inclination angle and left-right inclination angle) detectedby the vehicle body inclination sensor S4 is taken into the controller30.

The swing state sensor S5 outputs detection information related to aswing state of the upper swing body 3. The swing state sensor S5detects, for example, a swing angular velocity and a swing angle of theupper swing body 3. The swing state sensor S5 may include, for example,a gyro sensor, a resolver, a rotary encoder, or the like. A set ofdetection signals corresponding to the swing angle and the swing angularvelocity of the upper swing body 3 detected by the swing state sensor S5is taken into the controller 30.

The imaging device S6 as a space recognition device captures images ofthe periphery of the shovel 100. The imaging device S6 include a cameraS6F that captures images of the front side of the shovel 100, a cameraS6L that captures images of the left side of the shovel 100, a cameraS6R that captures images of the right side of the shovel 100, and acamera S6B that captures images of the rear side of the shovel 100. Theimaging device S6 may include an attachment camera attached to theattachment.

The camera S6F is mounted, for example, on the ceiling of the cabin 10,that is, inside the cabin 10. The camera S6F may also be attached to theoutside of the cabin such as the roof of the cabin 10 or the sidesurface of the boom 4. The camera S6L is attached to the left end of theupper surface of the upper swing body 3, the camera S6R is attached tothe right end of the upper surface of the upper swing body 3, and thecamera S6B is attached to the rear end of the upper surface of the upperswing body 3.

Each of the cameras (cameras S6F, S6B, S6L, and S6R) of the imagingdevice S6 is, for example, a monocular wide-angle camera having a verywide angle of view. The imaging device S6 may also be a stereo camera, adistance image camera, or the like. An image captured by the imagingdevice S6 is taken into the controller 30 via the display device 40.

The imaging device S6 as the space recognition device may function as anobject detection device. In such a case, the imaging device S6 maydetect an object present around the shovel 100. The object to bedetected may include, for example, a person (a helmet, a safety vest, orthe like), an animal, a vehicle (a dump truck or the like), aconstruction machine, a building, a hole, or the like. The imagingdevice S6 may also calculate a distance from the imaging device S6 orthe shovel 100 to the recognized object. The imaging device S6 as theobject detection device may be, for example, a stereo camera, a distanceimage sensor, or the like. The imaging device S6 as the spacerecognition device may be configured to be able to identify at least oneof a type, a position, a shape, and the like of an object around theshovel.

The space recognition device is, for example, a monocular camera havingan imaging element such as a CCD or a CMOS, and outputs a captured imageto the display device 40. The, the space recognition device may also beconfigured to calculate a distance from the space recognition device orthe shovel 100 to the recognized object. Furthermore, in addition to theimaging device S6, another object detection device such as an ultrasonicsensor, a millimeter wave radar, a LIDAR, or an infrared sensor may beprovided as the space recognition device.

In a case where a millimeter wave radar, an ultrasonic sensor, a laserradar, or the like is used as the space recognition device, a largenumber of signals (laser beams or the like) may be transmitted to theobject and, by receiving the reflected signals thereof, the distance andthe direction of the object may be detected from the reflected signals.In a case where the object detection device is provided, the imagingdevice S6 may be omitted.

Note that the imaging device S6 may be directly connected to thecontroller 30 so as to be able to communicate therewith.

A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B areattached to the boom cylinder 7. An arm rod pressure sensor S8R and anarm bottom pressure sensor S8B are attached to the arm cylinder 8.

A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9Bare attached to the bucket cylinder 9. The boom rod pressure sensor S7R,the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R,the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R,and the bucket bottom pressure sensor S9B are collectively referred toas “cylinder pressure sensors”.

The boom rod pressure sensor S7R detects the pressure in the rod sideoil chamber of the boom cylinder 7 (hereinafter referred to as “boom rodpressure”). The boom bottom pressure sensor S7B detects the pressure inthe bottom side oil chamber of the boom cylinder 7 (hereinafter referredto as “boom bottom pressure”).

The arm rod pressure sensor S8R detects the pressure in the rod side oilchamber of the arm cylinder 8 (hereinafter referred to as “arm rodpressure”). The arm bottom pressure sensor S8B detects the pressure inthe bottom side oil chamber of the arm cylinder 8 (hereinafter referredto as “arm bottom pressure”).

The bucket rod pressure sensor S9R detects the pressure in the rod sideoil chamber of the bucket cylinder 9 (hereinafter referred to as “bucketrod pressure”). The bucket bottom pressure sensor S9B detects thepressure in the bottom side oil chamber of the bucket cylinder 9(hereinafter referred to as “bucket bottom pressure”).

The positioning device PS measures the position and orientation of theupper swing body 3. The positioning device PS is, for example, a globalnavigation satellite system (GNSS) compass, detects the position and theorientation of the upper swing body 3. A detection signal correspondingto the position and the orientation of the upper swing body 3 is takeninto the controller 30. Among the functions of the positioning devicePS, the function of detecting the orientation of the upper swing body 3may be replaced by an orientation sensor attached to the upper swingbody 3.

The communication device Ti communicates with an external device such asan assist device 200 of the shovel 100 via a predetermined networkincluding mobile communication networks, satellite communicationnetworks, Internet networks, and the like with base stations asterminals. The assist device 200 of the shovel 100 may be used by, forexample, a manager who manages a worksite where the shovel 100 isoperated, or may be carried by an operator of the shovel 100. The assistdevice 200 may be, for example, a smartphone, a tablet-type terminaldevice, or the like.

The communication device Ti is, for example, a mobile communicationmodule conforming to a mobile communication standard such as Long TermEvolution (LTE), 4th Generation (4G), or 5th Generation (5G), or asatellite communication module for connecting to a satellitecommunication network.

The machine guidance part 50 executes, for example, control of theshovel 100 related to the machine guidance function. For example, themachine guidance part 50 transmits work information such as a distancebetween the target construction surface and the distal end portion ofthe attachment, specifically, a distance between the target constructionsurface and a work portion of the end attachment, to the operatorthrough the display device 40, the sound output device 43, or the like.

The data related to the target construction surface is stored in advancein the storage device 57, for example, as described above. The datarelated to the target construction surface is represented by, forexample, a reference coordinate system. The reference coordinate systemis, for example, the world geodetic system. The world geodetic system isa three-dimensional orthogonal XYZ coordinate system with the originbeing at the center of gravity of the earth, the X-axis being in thedirection of the intersection of the Greenwich meridian and the equator,the Y-axis being in the direction of 90 degrees east longitude, and theZ-axis being in the direction of the north pole.

The operator may set any points in a construction site as a referencepoint, and set a target track in a region to be excavated based on arelative positional relationship with the reference point through theinput device 42. The set target track is a target track for excavationthat is set below the ground. The work portion of the bucket 6 is, forexample, a tip of the bucket 6, a back surface of the bucket 6, or thelike. Here, the target track is calculated based on the shape of theground of the excavation target region before excavation or the shape ofthe temporarily placed fill (the shape of the excavation target). Theshape of the excavation target before excavation is acquired by thespace recognition device. The shape of the excavation target beforeexcavation may also be acquired based on the track of the tip of thebucket 6 at the time of previous excavation. The controller 30 thengenerates a target track to be excavated this time based on both theacquired shape of the excavation target before excavation and theexcavation operation plan. Thus, the controller 30 updates the targettrack to be excavated every time the loading operation is performed. Thecontroller 30 may also generate the target track so as to achieve thetarget weight.

In a case where, for example, a grapple or a lifting magnet is adoptedas the end attachment instead of the bucket 6, the distal end portion ofthe grapple or the bottom surface of the lifting magnet corresponds tothe work portion. The machine guidance part 50 notifies the operator ofthe work information through the display device the sound output device43, or the like, and guides the operator to operate the shovel 100through the operation device 26.

The machine guidance part 50 executes, for example, control of theshovel 100 related to a machine control function. For example, when theoperator manually performs the excavation operation, the machineguidance part 50 may automatically operate at least one of the boom 4,the arm 5, and the bucket 6 such that the target track and the tipposition of the bucket 6 match with each other.

The machine guidance part 50 acquires information from the boom anglesensor S1, the arm angle sensor S2, the bucket angle sensor S3, thevehicle body inclination sensor S4, the swing state sensor S5, theimaging device S6, the positioning device PS, the communication deviceTl, the input device 42, and the like.

The machine guidance part 50 then automatically controls the operationof the attachment such that the distal end portion of the attachment(specifically, a work portion such as the tip or the back surface of thebucket 6) follows the target track, for example, based on the acquiredinformation.

The machine guidance part 50 includes, as detailed functionalconfiguration elements related to the machine guidance function and themachine control function, a position calculation part 51, a distancecalculation part 52, an information transmission part 53, an automaticcontrol part 54, a swing angle calculation part 55, and a relative anglecalculation part 56.

The position calculation part 51 calculates the position of apredetermined positioning target. For example, the position calculationpart 51 calculates a coordinate point in the reference coordinate systemof the distal end portion of the attachment, specifically, the workportion such as the tip or the back surface of the bucket 6.Specifically, the position calculation part 51 calculates the coordinatepoint of the work portion of the bucket 6 from the elevation angles (theboom angle, the arm angle, and the bucket angle) of the boom 4, the arm5, and the bucket 6.

The distance calculation part 52 calculates a distance between twopositioning targets. For example, the distance calculation part 52calculates the distance between the distal end portion of theattachment, specifically, the work portion such as the tip or the backsurface of the bucket 6, and the target track. The distance calculationpart 52 may also calculate an angle (relative angle) between the backsurface as the work portion of the bucket 6 and the target track.

The information transmission part 53 transmits (notifies) various kindsof information to the operator of the shovel 100 through a predeterminednotification device such as the display device 40 or the sound outputdevice 43. The information transmission part 53 notifies the operator ofthe shovel 100 of magnitude (degrees) of the various distances and thelike calculated by the distance calculation part 52.

For example, (the magnitude of) the distance between the tip portion ofthe bucket 6 and the target track is transmitted to the operator usingat least one of the visual information by the display device 40 and theauditory information by the sound output device 43. The informationtransmission part 53 may transmit (the magnitude of) the relative anglebetween the back surface as the work part of the bucket 6 and the targettrack to the operator using at least one of the visual information bythe display device 40 and the auditory information by the sound outputdevice 43.

Furthermore, the information transmission part 53 may cause the displaydevice 40 to display the magnitude of the distance between the distalend portion of the attachment, specifically, the work portion of thebucket 6 and the target track, the magnitude of the relative anglebetween the back surface of the bucket 6 and the target track, or thelike, as the work information. Under the control of the controller 30,the display device 40 displays, for example, the work informationreceived from the information transmission part 53 together with theimage data received from the imaging device S6. The informationtransmission part 53 may transmit the magnitude of the vertical distanceto the operator using, for example, an image of an analog meter, animage of a bar graph indicator, or the like.

The automatic control part 54 automatically assists the manual operationof the shovel 100 by the operator through the operation device 26 byautomatically operating the actuator.

Specifically, the automatic control part 54 can individually andautomatically adjust the pilot pressures acting on the control valves(specifically, the control valve 173, the control valves 175L, 175R, andthe control valve 174) corresponding to the hydraulic actuators(specifically, the swing hydraulic motor 2A, the boom cylinder 7, andthe bucket cylinder 9), as will be described below. Thus, the automaticcontrol part 54 can automatically operate the respective hydraulicactuators.

The control related to the machine control function by the automaticcontrol part 54 may be executed, for example, when a predeterminedswitch included in the input device 42 is pressed. The predeterminedswitch is, for example, a machine control switch (hereinafter referredto as a “Machine Control (MC) switch”), and may be disposed as a knobswitch that is located at a distal end of a portion in the operationdevice 26 and gripped by the operator (for example, a lever device tooperate the arm 5). In the following description, it is assumed that themachine control function is enabled when the MC switch is pressed.

For example, when the MC switch or the like is pressed, the automaticcontrol part 54 automatically extends and contracts at least one of theboom cylinder 7 and the bucket cylinder 9 in accordance with theoperation of the arm cylinder 8 in order to assist the excavation workand the shaping work.

Specifically, when the operator manually performs a closing operation ofthe arm 5 (hereinafter, referred to as an “arm closing operation”), theautomatic control part 54 automatically extends and contracts at leastone of the boom cylinder 7 and the bucket cylinder 9 so that the targetconstruction surface matches the position of the work portion such asthe tip or the back surface of the bucket 6. In such a case, forexample, the operator can close the arm 5 while causing the tip or thelike of the bucket 6 to follow the target track only by performing thearm closing operation on the lever device that corresponds to theoperation of the arm 5.

Furthermore, when the MC switch or the like is pressed, the automaticcontrol part 54 may automatically rotate the swing hydraulic motor 2A(an example of actuators) in order to cause the upper swing body 3 toface the excavation target region for which the target track is to beset.

Hereinafter, control of causing the upper swing body 3 to face theexcavation target region by the controller 30 (the automatic controlpart 54) is referred to as “facing control”. Accordingly, the operatoror the like can cause the upper swing body 3 to face the excavationtarget region only by pressing a predetermined switch or by operating alever device 26C described below corresponding to a swing operation in astate in which the switch is pressed. The operator can also cause theupper swing body 3 to face the excavation target region and start themachine control function related to the excavation work of theexcavation target area or the like only by pressing the MC switch.

Specifically, when the lever device 26C corresponding to the swingoperation is operated in a state where a predetermined switch such asthe MC switch is pressed, it is determined whether or not the leverdevice 26C has been operated in a direction in which the upper swingbody 3 faces the excavation target region.

For example, when the lever device 26C has been operated in a directionin which the tip of the bucket 6 moves away from the excavation targetregion, the automatic control part 54 does not execute the facingcontrol. On the other hand, when the swing operation lever has beenoperated in a direction in which the tip of the bucket 6 approaches theexcavation target region, the automatic control part 54 executes thefacing control.

Thereby, the automatic control part 54 can operate the swing hydraulicmotor 2A so as to reduce the distance (or the swing angle) between thetip of the bucket 6 and the excavation target region. When thedifference therebetween becomes less than or equal to a predeterminedvalue or becomes zero, the automatic control part 54 stops the swinghydraulic motor 2A.

Furthermore, the automatic control part 54 may set a swing angle atwhich the difference is less than or equal to a predetermined value orzero as a target angle, and perform operation control of the swinghydraulic motor 2A so that the angle difference between the target angleand the current swing angle (specifically, the detection value based onthe detection signal of the swing state sensor S5) becomes zero. In sucha case, the swing angle is, for example, an angle of the front-back axisof the upper swing body 3 with respect to the reference direction.

As described above, in a case where the swing motor is mounted on theshovel 100 instead of the swing hydraulic motor 2A, the automaticcontrol part 54 performs the facing control with the swing motor (anexample of actuators) as a control target.

The swing angle calculation part 55 calculates a swing angle of theupper swing body 3. Thus, the controller 30 can specify the currentorientation of the upper swing body 3. The swing angle calculation part55 calculates the angle of the front-back axis of the upper swing body 3with respect to the reference direction as the swing angle based on, forexample, an output signal of a GNSS compass included in the positioningdevice PS.

The swing angle calculation part 55 may also calculate the swing anglebased on the detection signal of the swing state sensor S5. When areference point is set on the construction site, the swing anglecalculation part 55 may set a direction in which the reference point isviewed from the swing axis as the reference direction.

The pivot angle indicates the direction in which the attachmentoperating plane extends relative to the reference direction. Theoperating plane is, for example, a virtual plane that longitudinallytraverses the attachment, and is disposed so as to be perpendicular tothe swing plane. The swing plane is, for example, a virtual planeincluding the bottom surface of the swing frame perpendicular to theswing axis. For example, when the controller 30 (machine guidance part50) determines that the attachment operating plane matches theexcavation target region or the target track, the controller 30 thendetermines that the upper swing body 3 faces the target constructionsurface.

The relative angle calculation part 56 calculates a swing angle(relative angle) necessary for causing the upper swing body 3 to facethe excavation target region. The relative angle is, for example, arelative angle formed between the direction of the front-back axis ofthe upper swing body 3 when the upper swing body 3 faces the excavationtarget region and the current direction of the front-back axis of theupper swing body 3. The relative angle calculation part 56 calculatesthe relative angle based on, for example, the data related to theexcavation target region stored in the storage device 57 and the swingangle calculated by the swing angle calculation part 55.

When the lever device 26C corresponding to the swing operation isoperated in a state where a predetermined switch such as the MC switchis pressed, the automatic control part 54 determines whether or not theswing operation has been performed in a direction in which the upperswing body 3 faces the excavation target region.

The automatic control part 54 sets the relative angle calculated by therelative angle calculation part 56 as the target angle if it isdetermined that the upper swing body 3 has been operated to swing in adirection in which the upper swing body 3 faces the excavation targetregion. When the change in the swing angle after the lever device 26C isoperated reaches the target angle, the automatic control part 54 maydetermine that the upper swing body 3 faces the excavation target regionand stop the motion of the swing hydraulic motor 2A.

Accordingly, the automatic control part 54 can cause the upper swingbody 3 to face the excavation target region on the premise of theconfiguration illustrated in FIG. 2 . In the above-described embodimentof the facing control, an example of the facing control for theexcavation target region is described, however, the present disclosureis not limited thereto.

For example, even in the scooping operation when the temporarily placedearth and sand are loaded on the dump truck, the facing control of theswing operation may be performed so that the attachment faces the dumptruck. In such a case, the excavation track is changed every time thescooping operation is performed. Therefore, after the dumping to thedump truck, the front facing control is performed with respect to thenewly changed excavation track.

The swing hydraulic motor 2A includes a first port 2A1 and a second port2A2. A hydraulic sensor 21 detects the pressure of the hydraulic oil inthe first port 2A1 of the swing hydraulic motor 2A. A hydraulic sensor22 detects the hydraulic oil in the second port 2A2 of the swinghydraulic motor 2A. A detection signal corresponding to the dischargepressures detected by the hydraulic sensors 21, 22 is taken into thecontroller 30.

Furthermore, the first port 2A1 is connected to a hydraulic oil tank viaa relief valve 23. The relief valve 23 opens when the pressure on thefirst port 2A1 side reaches predetermined relief pressure, anddischarges the hydraulic oil on the first port 2A1 side to the hydraulicoil tank. Similarly, the second port 2A2 is connected to the hydraulicoil tank via a relief valve 24. The relief valve 24 opens when thepressure on the second port 2A2 side reach predetermined reliefpressure, and discharges the hydraulic oil on the second port 2A2 sideto the hydraulic oil tank. Furthermore, it is not always necessary toperform the facing control using the machine guidance function or themachine control function. The facing operation and the excavationoperation may be performed by manually by the operator.

Next, a hydraulic system of the shovel 100 according to this embodimentwill be described with reference to FIG. 3 .

FIG. 3 is a diagram for schematically illustrating an example of thehydraulic system configuration of the shovel 100 according to thisembodiment.

Note that, in FIG. 3 , a path for a mechanical power system, a hydraulicoil line, a pilot line, and a path for an electric control system areindicated by a double line, a solid line, a dashed line, and a dottedline, respectively, as in the case of FIG. 2 and the like.

The hydraulic system implemented by the hydraulic circuit circulates thehydraulic oil from each of the main pumps 14L, 14R driven by the engine11 to the hydraulic oil tank via center bypass oil paths C1L, C1R andparallel oil paths C2L, C2R.

The center bypass oil path C1L starts from the main pump 14L, passesthrough the control valves 171, 173, 175L, and 176L arranged in thecontrol valve unit 17 in this order, and reaches the hydraulic oil tank.

The center bypass oil path C1R starts from the main pump 14R, passesthrough the control valves 172, 174, 175R, and 176R arranged in thecontrol valve unit 17 in this order, and reaches the hydraulic oil tank.

The control valve 171 is a spool valve that supplies the hydraulic oildischarged from the main pump 14L to the traveling hydraulic motor 1Land discharges the hydraulic oil discharged from the traveling hydraulicmotor 1L to the hydraulic oil tank.

The control valve 172 is a spool valve that supplies the hydraulic oildischarged from the main pump 14R to the traveling hydraulic motor 1Rand discharges the hydraulic oil discharged from the traveling hydraulicmotor 1R to the hydraulic oil tank.

The control valve 173 is a spool valve that supplies the hydraulic oildischarged from the main pump 14L to the swing hydraulic motor 2A anddischarges the hydraulic oil discharged from the swing hydraulic motor2A to the hydraulic oil tank.

The control valve 174 is a spool valve that supplies the hydraulic oildischarged from the main pump 14R to the bucket cylinder 9 anddischarges the hydraulic oil in the bucket cylinder 9 to the hydraulicoil tank.

The control valves 175L, 175R are spool valves that supply the hydraulicoil discharged from the main pumps 14L, 14R to the boom cylinder 7 anddischarge the hydraulic oil in the boom cylinder 7 to the hydraulic oiltank.

The control valves 176L, 176R supply the hydraulic oil discharged fromthe main pumps 14L, 14R to the arm cylinder 8 and discharge thehydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

In accordance with the pilot pressure acting on the pilot port, each ofthe control valves 171, 172, 173, 174, 175L, 175R, 176L, and 176Radjusts the flow rate of the hydraulic oil supplied to and dischargedfrom the respective hydraulic actuators or switches the flow direction.

The parallel oil path C2L supplies the hydraulic oil of the main pump14L to the control valves 171, 173, 175L, and 176L in parallel with thecenter bypass oil path C1L.

Specifically, the parallel oil path C2L is branched from the centerbypass oil path C1L at the upstream side of the control valve 171, andis configured to be able to supply the hydraulic oil of the main pump14L in parallel to each of the control valves 171, 173, 175L, and 176R.Accordingly, in a case where the flow of the hydraulic oil passingthrough the center bypass oil path C1L is limited or blocked by any oneof the control valves 171, 173 and 175L, the parallel oil path C2L cansupply the hydraulic oil to the control valve which is arranged furtherdownstream.

The parallel oil path C2R supplies the hydraulic oil of the main pump14R to the control valves 172, 174, 175R, and 176R in parallel with thecenter bypass oil path C1R. Specifically, the parallel oil path C2R isbranched from the center bypass oil path C1R at the upstream side of thecontrol valve 172, and is configured to be able to supply the hydraulicoil of the main pump 14R in parallel to each of the control valves 172,174, 175R, and 176R. Accordingly, in a case where the flow of thehydraulic oil passing through the center bypass oil path C1R is limitedor blocked by any one of the control valves 172, 174 and 175R, theparallel oil path C2R can supply the hydraulic oil to the control valvewhich is arranged further downstream.

The regulators 13L, 13R adjust the discharge amount of the main pumps14L, 14R by adjusting the tilt angles of the swash plates of the mainpumps 14L, 14R under the control of the controller 30.

The discharge pressure sensor 28L detects a discharge pressure of themain pump 14L, and a detection signal corresponding to the detecteddischarge pressure is taken into the controller 30. The same applies tothe discharge pressure sensor 28R. Thus, the controller 30 can controlthe regulators 13L, 13R in accordance with the discharge pressures ofthe main pumps 14L, 14R.

The center bypass oil paths C1L, C1R are provided with throttles 18L,18R between the most downstream control valves 176L, 176R and thehydraulic oil tank, respectively. Thus, the flow of the hydraulic oildischarged from the main pumps 14L, 14R is limited by the throttles 18L,18R. The throttles 18L, 18R generate control pressures for controllingthe regulators 13L, 13R, respectively.

Control pressure sensors 19L, 19R detect a control pressure, and adetection signal corresponding to the detected control pressure is takeninto the controller 30.

The controller 30 may control the regulators 13L, 13R in accordance withthe discharge pressures of the main pumps 14L, 14R detected by thedischarge pressure sensors 28L, 28R to adjust the discharge amount ofthe main pumps 14L, 14R. For example, the controller 30 may decrease thedischarge amount by controlling the regulator 13L and adjusting theswash plate tilt angle of the main pump 14L in accordance with anincrease in the discharge pressure of the main pump 14L. The sameapplies to the regulator 13R. Thus, the controller 30 can perform thewhole horsepower control of the main pumps 14L, 14R so that theabsorption horsepower of the main pumps 14L, 14R represented by theproduct of the discharge pressure and the discharge amount does notexceed the output horsepower of the engine 11.

Furthermore, the controller 30 may adjust the discharge amount of themain pumps 14L, 14R by controlling the regulators 13L, 13R in accordancewith the control pressures detected by the control pressure sensors 19L,19R. For example, the controller 30 decreases the discharge amount ofthe main pumps 14L, 14R as the control pressure increases, and increasesthe discharge amount of the main pumps 14L, 14R as the control pressuredecreases.

Specifically, in the case of a standby state (state illustrated in FIG.3 ) in which none of the hydraulic actuators in the shovel 100 isoperated, the hydraulic oil discharged from the main pumps 14L, 14Rpasses through the center bypass oil paths C1L, C1R and reaches thethrottles 18L, 18R. The flow of the hydraulic oil discharged from themain pumps 14L, 14R increases the control pressures generated upstreamof the throttles 18L, 18R. As a result, the controller 30 reduces thedischarge amount of the main pumps 14L, 14R to the allowable minimumdischarge amount, and suppresses the pumping loss when the dischargedhydraulic oil passes through the center bypass oil paths C1L, C1R.

On the other hand, when any of the hydraulic actuators are operatedthrough the operation device 26, the hydraulic oil discharged from themain pumps 14L, 14R flows into the hydraulic actuators to be operatedthrough the control valves corresponding to the hydraulic actuators tobe operated.

Then, the flow of the hydraulic oil discharged from the main pumps 14L,14R reduces or eliminates the amount of the hydraulic oil that reachesthe throttles 18L, 18R, thereby reducing the control pressures generatedupstream of the throttles 18L, 18R. Thereby, the controller 30 canincrease the discharge amount of the main pumps 14L, 14R, circulate asufficient amount of hydraulic oil to the hydraulic actuators to beoperated, and reliably drive the hydraulic actuators to be operated.

Next, a configuration in which the controller 30 operates the actuatorsby the machine control function will be described with reference to theFIG. 4A to FIG. 4D. FIG. 4A to FIG. 4D are diagrams in which a part ofthe hydraulic system is extracted. Specifically, FIG. 4A is a diagram inwhich a hydraulic system part related to operations of the arm cylinder8 is extracted, and FIG. 4B is a diagram in which a hydraulic systempart related to operations of the boom cylinder 7 is extracted. FIG. 4Cis a diagram in which a hydraulic system part related to operations ofthe bucket cylinder 9 is extracted, and FIG. 4D is a diagram in which ahydraulic system part related to operations of the swing hydraulic motor2A is extracted.

As illustrated in the FIG. 4A to the FIG. 4D, the hydraulic systemincludes the proportional valve 31. The proportional valve 31 includesproportional valves 31AL to 31DL and 31AR to 31DR.

The proportional valve 31 functions as a control valve for machinecontrol. The proportional valve 31 is disposed in a conduit connectingthe pilot pump 15 and a pilot port of a corresponding control valve inthe control valve unit 17, and is configured to be able to change a flowpath area of the conduit. In this embodiment, the proportional valve 31operates in response to a control command output from the controller 30.

The controller 30 can therefore supply the hydraulic oil discharged fromthe pilot pump 15 to the pilot port of the corresponding control valvein the control valve unit 17 via the proportional valve 31 regardless ofoperations of the operation device 26 by the operator. The controller 30can then apply the pilot pressure generated by the proportional valve 31to the pilot port of the corresponding control valve.

With this configuration, even when a specific operation device 26 is notoperated, the controller 30 can operate the hydraulic actuatorcorresponding to the specific operation device 26. The controller 30 canalso forcibly stop the operation of the hydraulic actuator correspondingto the specific operation device 26 even when a specific operationdevice 26 is operated.

For example, as illustrated in FIG. 4A, the left operation lever 26L isused to operate the arm 5. Specifically, the left operation lever 26Luses the hydraulic oil discharged from the pilot pump 15 to apply thepilot pressure corresponding to the operation in the front-reardirection to the pilot port of the control valve 176.

More specifically, the left operation lever 26L, if it is operated inthe arm closing direction (rearward direction), applies the pilotpressure corresponding to the operation amount to the right pilot portof the control valve 176L and the left pilot port of the control valve176R. Also, the left operation lever 26L, if it is operated in the armopening direction (forward direction), applies the pilot pressurecorresponding to the operation amount to the left pilot port of thecontrol valve 176L and the right pilot port of the control valve 176R.

A switch NS is provided on the left operation lever 26L. In thisembodiment, the switch NS is a push-button switch provided at the distalend of the left operation lever 26L. The operator can operate the leftoperation lever 26L while pressing the switch NS. The switch NS may beprovided on the right operation lever 26R or may be provided at anotherposition in the cabin 10.

Operation sensor 29LA detects the content of an operation performed bythe operator on the left operation lever 26L in the front-reardirection, and outputs the detected value to the controller 30.

The proportional valve 31AL operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theright pilot port of the control valve 176L and the left pilot port ofthe control valve 176R via the proportional valve 31AL is adjusted.

The proportional valve 31AR operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theleft pilot port of the control valve 176L and the right pilot port ofthe control valve 176R via the proportional valve 31AR is adjusted. Theproportional valve 31AL can adjust the pilot pressure so that thecontrol valve 176L and the control valve 176R can be stopped at anyvalve position. Similarly, the proportional valve 31AR can adjust thepilot pressure so that the control valve 176L and the control valve 176Rcan be stopped at any valve position.

With this configuration, the controller 30 can supply the hydraulic oildischarged from the pilot pump 15 to the right pilot port of the controlvalve 176L and the left pilot port of the control valve 176R via theproportional valve 31AL in response to the arm closing operation by theoperator. The controller 30 can also supply the hydraulic oil dischargedfrom the pilot pump 15 to the right pilot port of the control valve 176Land the left pilot port of the control valve 176R via the proportionalvalve 31AL regardless of the arm closing operation by the operator. Thatis, the controller 30 can open the arm 5 in response to the arm openingclosing by the operator or regardless of the arm opening closing by theoperator.

Furthermore, the controller 30 can supply the hydraulic oil dischargedfrom the pilot pump 15 to the left pilot port of the control valve 176Land the right pilot port of the control valve 176R via the proportionalvalve 31AR according to the arm opening operation by the operator. Thecontroller 30 can also supply the hydraulic oil discharged from thepilot pump 15 to the left pilot port of the control valve 176L and theright pilot port of the control valve 176R via the proportional valve31AR regardless of the arm opening operation by the operator. That is,the controller 30 can open the arm 5 in response to the arm openingoperation by the operator or regardless of the arm opening operation bythe operator.

With this configuration, even when the arm closing operation isperformed by the operator, the controller 30 can reduce the pilotpressure acting on the pilot port on the closing side of the controlvalve 176 (the left pilot port of the control valve 176L and the rightpilot port of the control valve 176R) as necessary to forcibly stop theclosing operation of the arm 5. The same applies to a case where theopening operation of the arm 5 is forcibly stopped when the arm openingoperation is performed by the operator.

Alternatively, even when the arm closing operation is performed by theoperator, the controller 30 may forcibly stop the closing operation ofthe arm 5 by controlling the proportional valve 31AR as necessary toincrease the pilot pressures acting on the pilot ports (the right pilotport of the control valve 176L and the left pilot port of the controlvalve 176R) on the opening side of the control valve 176 opposite to thepilot ports on the closing side of the control valve 176 and to forciblyreturn the control valve 176 to the neutral position. The same appliesto a case where the opening operation of the arm 5 is forcibly stoppedwhen the arm opening operation is performed by the operator.

Although description with reference to the FIG. 4B to FIG. 4D isomitted, the same applies to a case where the operation of the boom 4 isforcibly stopped when the operator performs a boom raising operation ora boom lowering operation, a case where the operation of the bucket 6 isforcibly stopped when the operator performs a bucket closing operationor a bucket opening operation, and a case where the swing operation ofthe upper swing body 3 is forcibly stopped when the operator performsthe swing operation. The same applies also to a case where the travelingoperation of the lower traveling body 1 is forcibly stopped when thetraveling operation is performed by the operator.

As illustrated in FIG. 4B, the right operation lever 26R is used tooperate the boom 4. Specifically, the right operation lever 26R uses thehydraulic oil discharged from the pilot pump 15 to apply the pilotpressure corresponding to the operation in the front-rear direction tothe pilot port of the control valve 175.

More specifically, the right operation lever 26R, if it is operated inthe boom raising direction (rearward direction), applies the pilotpressure corresponding to the operation amount to the right pilot portof the control valve 175L and the left pilot port of the control valve175R. Also, the right operation lever 26R, if it is operated in the boomlowering direction (forward direction), applies the pilot pressurecorresponding to the operation amount to the right pilot port of thecontrol valve 175R.

Operation sensor 29RA detects the content of an operation performed bythe operator on the right operation lever 26R in the front-reardirection, and outputs the detected value to the controller 30.

The proportional valve 31BL operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theright pilot port of the control valve 175L and the left pilot port ofthe control valve 175R via the proportional valve 31BL is adjusted. Theproportional valve 31BR operates in response to a control command(current command) output from the controller 30.

Then, the pilot pressure by the hydraulic oil introduced from the pilotpump 15 to the right pilot port of the control valve 175R via theproportional valve 31BR is adjusted. The proportional valve 31BL canadjust the pilot pressure so that the control valve 175L and the controlvalve 175R can be stopped at any valve position. The proportional valve31BR can also adjust the pilot pressure so that the control valve 175Rcan be stopped at any valve position.

With this configuration, the controller 30 can supply the hydraulic oildischarged from the pilot pump 15 to the right pilot port of the controlvalve 175L and the left pilot port of the control valve 175R via theproportional valve 31BL in response to the boom raising operation by theoperator. The controller 30 can also supply the hydraulic oil dischargedfrom the pilot pump 15 to the right pilot port of the control valve 175Land the left pilot port of the control valve 175R via the proportionalvalve 31BL regardless of the boom raising operation by the operator.That is, the controller 30 can raise the boom 4 in response to the boomraising operation by the operator or regardless of the boom raisingoperation by the operator.

Furthermore, the controller 30 can supply the hydraulic oil dischargedfrom the pilot pump 15 to the right pilot port of the control valve 175Rvia the proportional valve 31BR in response to the boom loweringoperation by the operator. The controller 30 can also supply thehydraulic oil discharged from the pilot pump 15 to the right pilot portof the control valve 175R via the proportional valve 31BR regardless ofthe boom lowering operation by the operator. That is, the controller 30can lower the boom 4 in response to the boom lowering operation by theoperator or regardless of the boom lowering operation by the operator.

As illustrated in FIG. 4C, the right operation lever 26R is also used tooperate the bucket 6. Specifically, the right operation lever 26R usesthe hydraulic oil discharged from the pilot pump 15 to apply the pilotpressure corresponding to the operation in the left-right direction tothe pilot port of the control valve 174. More specifically, the rightoperation lever 26R, if it is operated in the bucket closing direction(left direction), applies the pilot pressure corresponding to theoperation amount to the left pilot port of control valve 174. The rightoperation lever 26R, if it is operated in the bucket opening direction(right direction), applies the pilot pressure corresponding to theoperation amount to the right pilot port of the control valve 174.

The operation sensor 29RB detects the content of an operation performedby the operator on the right operation lever 26R in the left-rightdirection, and outputs the detected value to the controller 30.

The proportional valve 31CL operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theleft pilot port of the control valve 174 via the proportional valve 31CLis adjusted. The proportional valve 31CR operates in response to acontrol command (current command) output from the controller 30. Then,the pilot pressure by the hydraulic oil introduced from the pilot pump15 to the right pilot port of the control valve 174 via the proportionalvalve 31CR is adjusted.

The proportional valve 31CL can adjust the pilot pressure so that thecontrol valve 174 can be stopped at any valve position. Similarly, theproportional valve 31CR can adjust the pilot pressure so that thecontrol valve 174 can be stopped at any valve position.

With this configuration, the controller 30 can supply the hydraulic oildischarged from the pilot pump 15 to the left pilot port of the controlvalve 174 via the proportional valve 31CL in response to the bucketclosing operation by the operator. Also, the controller 30 can supplythe hydraulic oil discharged from the pilot pump 15 to the left pilotport of the control valve 174 via the proportional valve 31CL regardlessof the bucket closing operation by the operator. That is, the controller30 can close the bucket 6 in response to the bucket closing operation bythe operator or regardless of the bucket closing operation by theoperator.

Furthermore, the controller 30 can supply the hydraulic oil dischargedfrom the pilot pump 15 to the right pilot port of the control valve 174via the proportional valve 31CR in response to the bucket openingoperation by the operator. The controller 30 can also supply thehydraulic oil discharged from the pilot pump 15 to the right pilot portof the control valve 174 via the proportional valve 31CR regardless ofthe bucket opening operation by the operator. That is, the controller 30can open the bucket 6 in response to the bucket opening operation by theoperator or regardless of the bucket opening operation by the operator.

As illustrated in FIG. 4D, the left operation lever 26L is also used tooperate the swing mechanism 2. Specifically, the left operation lever26L uses the hydraulic oil discharged from the pilot pump 15 to applythe pilot pressure corresponding to the operation in the left-rightdirection to the pilot port of the control valve 173. More specifically,the left operation lever 26L, if it is operated in the left swingdirection (left direction), applies the pilot pressure corresponding tothe operation amount to the left pilot port of control valve 173. Also,the left operation lever 26L, if it is operated in the right swingdirection (right direction), applies the pilot pressure corresponding tothe operation amount to the right pilot port of the control valve 173.

The operation sensor 29LB detects the content of an operation performedby the operator on the left operation lever 26L in the left-rightdirection, and outputs the detected value to the controller 30.

The proportional valve 31DL operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theleft pilot port of the control valve 173 via the proportional valve 31DLis adjusted.

The proportional valve 31DR operates in response to a control command(current command) output from the controller 30. Then, the pilotpressure by the hydraulic oil introduced from the pilot pump 15 to theright pilot port of the control valve 173 via the proportional valve31DR is adjusted. The proportional valve 31DL can adjust the pilotpressure so that the control valve 173 can be stopped at any valveposition. Similarly, the proportional valve 31DR can adjust the pilotpressure so that the control valve 173 can be stopped at any valveposition.

With this configuration, the controller 30 can supply the hydraulic oildischarged from the pilot pump 15 to the left pilot port of the controlvalve 173 via the proportional valve 31DL in response to the left swingoperation by the operator. The controller 30 can also supply thehydraulic oil discharged from the pilot pump 15 to the left pilot portof the control valve 173 via the proportional valve 31DL regardless ofthe left swing operation by the operator. That is, the controller 30 canswing the swing mechanism 2 to the left in response to the left swingoperation by the operator or regardless of the left swing operation bythe operator.

Furthermore, the controller 30 can supply the hydraulic oil dischargedfrom the pilot pump 15 to the right pilot port of the control valve 173via the proportional valve 31DR in response to the right swing operationby the operator. The controller 30 can also supply the hydraulic oildischarged from the pilot pump 15 to the right pilot port of the controlvalve 173 via the proportional valve 31DR regardless of the right swingoperation by the operator. That is, the controller 30 can swing theswing mechanism 2 to the right in response to the right swing operationby the operator or regardless of the right swing operation by theoperator.

The shovel 100 may have a configuration for automatically moving thelower traveling body 1 forward and backward. In such a case, thehydraulic system part related to operations of a left travelinghydraulic motor 2ML and the hydraulic system part related to operationsof a right traveling hydraulic motor 2MR may be configured in the samemanner as the hydraulic system part related to operations of the boomcylinder 7 and the like.

The shovel 100 may also include a configuration for automaticallyoperating the bucket tilt mechanism. In such a case, the hydraulicsystem part related to the bucket tilt cylinder constituting the buckettilt mechanism may be configured in the same manner as the hydraulicsystem part related to operations of the boom cylinder 7 or the like.

Although the electric operation lever has been described as the form ofthe operation device 26, a hydraulic operation lever may be employedinstead of the electric operation lever. In such a case, the leveroperation amount of the hydraulic operation lever may be detected in theform of pressure by a pressure sensor and input to the controller 30.Furthermore, a solenoid valve may be disposed between the operationdevice 26 as the hydraulic operation lever and the pilot port of eachcontrol valve.

The solenoid valve is configured to operate in accordance with anelectrical signal from the controller 30. With this configuration, in acase where a manual operation using the operation device 26 as thehydraulic operation lever is performed, the operation device 26 can moveeach control valve by increasing or decreasing the pilot pressureaccording to the lever operation amount. Each control valve may beconstituted by a solenoid spool valve. In such a case, the solenoidspool valve operates in accordance with an electric signal from thecontroller 30 corresponding to the lever operation amount of theelectric operation lever.

Next, with reference to FIG. 5 , details of a configuration related toan earth and sand weight detection function of the shovel 100 accordingto this embodiment will be described. FIG. 5 is a diagram forschematically illustrating an example of components related to the earthand sand weight detection function in the shovel 100 according to thisembodiment.

As described above with reference to FIG. 3 , the controller 30 includesthe earth and sand weight processing part 60 as a functional partrelated to the detection function of the weight of the earth and sandexcavated by the bucket 6.

The earth and sand weight processing part 60 includes a weightcalculation part 61, a maximum load amount detection part 62, a loadamount calculation part 63, a remaining load amount calculation part 64,a center-of-gravity calculation part 65, a display control part 66, anda reference value correction part 67.

Here, an example of operations of loading earth and sand (load) into adump truck by the shovel 100 according to this embodiment will bedescribed.

First, the shovel 100 controls the attachment to excavate earth and sandby the bucket 6 at the excavation position (excavation operation). Theshovel 100 then causes the upper swing body 3 to swing to move thebucket 6 from the excavation position to the dumping position (swingoperation).

A cargo bed of the dump truck is disposed under the dumping position. Atthe dumping position, the shovel 100 controls the attachment to dump theearth and sand in the bucket 6, thereby loading the earth and sand inthe bucket 6 onto the cargo bed of the dump truck (earth and sanddumping operation).

Next, the shovel 100 causes the upper swing body 3 to swing to move thebucket 6 from the dumping position to the excavation position (swingoperation). By repeating these operations, the shovel 100 loads theexcavated earth and sand onto the cargo bed of the dump truck.

The weight calculation part 61 calculates the weight of the earth andsand (load) in the bucket 6 based on the thrust of the boom cylinder 7.

For example, the weight calculation part 61 calculates the earth andsand weight based on the thrust of the boom cylinder 7, the distancefrom the pin connecting the upper swing body 3 and the boom 4 to thecenter of the gravity of the earth and sand, and the equation of themoment around the pin connecting the upper swing body 3 and the boom 4.

The weight calculation part 61 then calculates the weight of the load inbucket 6 by subtracting the weight of the entire bucket 6 when it isdetermined that the bucket 6 is in an empty state from the calculatedweight of the entire bucket 6.

In the following description, the weight of the bucket 6 when it isdetermined that the bucket 6 is in the empty state may be referred to asa reference value which is used for subtraction in the calculation ofthe load amount by the weight calculation part 61. The reference valueincludes both an initial value indicating the weight of the bucket 6stored in the controller 30 at the time of factory shipment or the likeof the shovel 100 and a past reference value set in a past loadingoperation. Details of the reference value will be described later.

Although, in this embodiment, the earth and sand (load) is described asbeing loaded on the bucket 6, the load is, in other words, what isconveyed by the end attachment of the shovel 100. Therefore, the earthand sand can be said to be a load object conveyed by the end attachmentof the shovel 100.

In this embodiment, the timing at which it is determined that the bucket6 is in the empty state is notified to the operator of the shovel 100 asthe timing at which the reference value is corrected. Therefore, in thisembodiment, the operator does not need to confirm whether or not thebucket 6 is empty. In this embodiment, the operator can accurately knowthe timing for correcting the reference value.

The maximum load amount detection part 62 detects the maximum loadamount of the dump truck on which earth and sand are to be loaded. Forexample, the maximum load amount detection part 62 specifies a dumptruck on which earth and sand are to be loaded based on images capturedby the imaging device S6. “Based on the image captured by the imagingdevice S6” means, for example, using information obtained by performingone or more image processes on the image captured by the imaging deviceS6. The maximum load amount of the dump truck may be manually input bythe operator.

Next, the maximum load amount detection part 62 detects the maximum loadamount of the dump truck based on the specified image of the dump truck.For example, the maximum load amount detection part 62 determines thevehicle type (size or the like) of the dump truck based on the specifiedimage of the dump truck.

Specifically, for example, the maximum load amount detection part 62 mayhave a table in which the vehicle type and the maximum load amount areassociated with each other, and, based on both the vehicle typedetermined from the image and the table, the maximum load amountdetection part obtains the maximum load amount of the dump truck. Notethat the maximum load amount of the dump truck, the vehicle type, andthe like may be input by the input device 42, and the maximum loadamount detection part 62 may obtain the maximum load amount of the dumptruck based on the input information of the input device 42.

The load amount calculation part 63 calculates the weight of the earthand sand loaded on the dump truck. That is, every time the earth andsand in the bucket 6 is dumped onto the cargo bed of the dump truck, theload amount calculation part 63 adds the weight of the earth and sand inthe bucket 6 calculated by the weight calculation part 61 to calculatethe loaded amount (total weight) which is the total weight of the earthand sand loaded onto the cargo bed of the dump truck. When the dumptruck to be loaded with earth and sand is changed to new dump truck, theload amount is reset.

The remaining load amount calculation part 64 calculates the differencebetween the maximum load amount of the dump truck detected by themaximum load amount detection part 62 and the current loaded amountcalculated by the load amount calculation part 63 as the remaining loadamount. The remaining load amount is the remaining weight of the earthand sand that can be loaded on the dump truck.

The center-of-gravity calculation part 65 calculates the center ofgravity of the earth and sand (load) in the bucket 6. Note that a methodof calculating the center of gravity of the earth and sand will bedescribed below.

The display control part 66 displays, on the main screen (for example,another screen) displayed on the display device 40, an icon image forguiding transition to the loading work screen (for example, a screen).Details of the main screen and the loading work screen will be describedlater.

Upon reception of selection of the input device 42 corresponding to theicon image in the display device 40, the display control part 66transitions the main screen to the screen for the loading work. On theloading work screen of this embodiment, an icon image corresponding tothe input device 42 for correcting (updating) the reference value in thecalculation of the weight of the load by the weight calculation part 61is displayed. In the following description, this icon image may bereferred to as a correction icon image.

The display control part 66 may cause the display device 40 to displaythe weight of the earth and sand in the bucket 6 calculated by theweight calculation part 61, the maximum load amount of the dump truckdetected by the maximum load amount detection part 62, the loaded amounton the dump truck (the total weight of the earth and sand loaded ontothe cargo bed) calculated by the load amount calculation part 63, andthe remaining load amount of the dump truck (the remaining weight of theearth and sand that can be loaded thereon) calculated by the remainingload amount calculation part 64.

In a case where the load amount exceeds the maximum load amount, thedisplay control part 66 may cause the display device 40 to display awarning. Furthermore, in a case where the calculated weight of the earthand sand in the bucket 6 exceeds the remaining load amount, the displaycontrol part 66 may cause the display device 40 to display a warning.Note that the warning is not limited to the case of being displayed onthe display device 40, and may be a sound output by the sound outputdevice 43. Thus, earth and sand can be prevented from being loaded inexcess of the maximum load amount of the dump truck.

At the timing when it is determined that the bucket 6 is in the emptystate, the display control part 66 also changes the display mode of thecorrection icon image displayed on the loading work screen. In thisembodiment, the operator is notified of the timing at which thereference value is corrected by changing the display mode of thecorrection icon image.

The reference value correction part 67 corrects the reference value usedwhen the weight calculation part 61 calculates the weight of the load.The reference value correction part 67 compares the weight of the bucket6 calculated by the weight calculation part 61 with the currently setreference value, and in a case where a difference between the weight ofthe bucket 6 and the currently set reference value is larger than apredetermined threshold value, determines that the bucket 6 is in astate after excavation in which earth and sand and the like are loaded.In such a case, the reference value correction part 67 prohibits theweight calculation part 61 from correcting the reference value.

Specifically, the reference value correction part 67 causes the displaycontrol part 66 to display the correction icon image on the loading workscreen in a display mode indicating that the selection of thecorresponding input device 42 is invalid, and prohibits the selection ofthe input device 42 corresponding to the correction icon image. Detailsof the display mode of the correction icon image will be describedlater.

In a case where the difference between the weight of the bucket 6 andthe currently set reference value is less than or equal to thepredetermined threshold value, the reference value correction part 67determines that the bucket 6 is in the empty state after dumping, andallows the correction of the reference value.

Specifically, the reference value correction part 67 causes the displaycontrol part 66 to display the correction icon image on the loading workscreen in a display mode indicating that the corresponding input device42 is selectable, and allows the input device 42 corresponding to thecorrection icon image to be selected.

When the input device 42 corresponding to the correction icon image isselected, the reference value correction part 67 sets the weight of thebucket 6 at this time as a new reference value. In other words, thereference value correction part 67 updates the initial value stored inthe controller 30 at the time of factory shipment or the reference valueset in the past loading operation.

Hereinafter, the reference value of this embodiment will be describedwith reference to FIG. 6 . FIG. 6 is a diagram for explaining thereference value. In FIG. 6 , the vertical axis represents weight, andthe horizontal axis represents time.

In the example of FIG. 6 , a change in the weight of the bucket 6 duringthe loading operation of the shovel 100 is illustrated. FIG. 6illustrates a case where the bucket 6 after excavation dumps the earthand sand loaded in the bucket 6 at a timing t1. At this time, theinitial value has been set in the shovel 100 as the reference value tobe subtracted from the weight of the bucket 6.

In FIG. 6 , a weight W1 is set as the initial value, and a differencebetween a weight W3 and a weight W1 is set as a predetermined thresholdvalue TH1 for determining whether or not the bucket 6 is empty.

In FIG. 6 , in the state before the timing t1, the weight of the bucket6 is a weight W4, and a difference between the weight W4 and the weightW1 is larger than the predetermined threshold value TH1. Therefore, thereference value correction part 67 determines that the bucket 6 is inthe state in which the earth and sand are loaded, and prohibits thecorrection of the reference value.

At a timing t2 after the timing t1, it is a state after the earth andsand are dumped from the bucket 6. In such a case, a difference TH2between the weight W2 and the weight W1 of the bucket 6 is less than orequal to the predetermined threshold value TH1.

In such a case, the reference value correction part 67 determines thatthe bucket 6 is in the empty state, and allows the correction of thereference value. Specifically, the reference value correction part 67sets the weight W2 of the bucket 6 at the time when it is determinedthat the bucket 6 is in the empty state as the reference value to bereferred to in the subsequent processing of the weight calculation part61.

In other words, the reference value correction part 67 sets a valueobtained by adding the difference TH2 between the weight W2 and theweight W1 of the bucket 6 to the weight W1 which is the reference valueafter the previous dumping as the reference value to be referred to inthe subsequent processing.

The difference TH2 between the weight W2 and the weight W1 of the bucket6 is, for example, the weight of the earth and sand that sticks to theinside of the bucket 6 and is not dumped when dumping the earth andsand. In the loading operation, for example, depending on the type ofthe earth and sand, the temperature of the hydraulic oil of the shovel100, or the like, the earth and sand may adhere to the tip or the likeof the bucket 6, and a small amount of earth and sand may remain in thebucket 6.

In such a case, when the weight of the load on the bucket 6 iscalculated using the initial value at the time of factory shipment asthe reference value, the weight of the earth and sand remaining in thebucket 6 and not dumped onto the cargo bed of the dump truck is alsoincluded in the weight of the load dumped onto the cargo bed of the dumptruck. Although the initial value is used as the set reference value inthe above embodiment, the reference value set in the past loadingoperation may be used as the reference value for calculating thedifference.

In this embodiment, the weight of the load excluding the weight of theearth and sand remaining in the bucket 6 and not dumped can becalculated by performing the correction using the weight of the bucket 6after dumping the load from the bucket 6 as the reference value.

In this embodiment, as described above, when the weight of the load inthe bucket 6 is calculated, the reference value to be subtracted fromthe weight of the entire bucket 6 is corrected, so that the accuracy ofthe calculation of the weight of the load in the bucket 6 can beimproved. In the above-described embodiment, when the difference betweenthe calculated weight and the reference value is less than or equal tothe predetermined threshold value TH1, the controller 30 determines thatit is time to correct the reference value; however, the determinationmethod is not limited thereto.

For example, when the weight calculated by the weight calculation part61 is less than or equal to a predetermined value, the controller 30 maydetermine that it is the timing for correcting the reference value (thebucket 6 is in the empty state). The controller 30 may also determinethe timing for correcting the reference value (the bucket 6 is in theempty state) based on the output of the space recognition device.

Next, the operation of the earth and sand weight processing part 60 ofthis embodiment will be described with reference to FIG. 7 . FIG. 7 is aflowchart for explaining the operation of the earth and sand weightprocessing part.

In the earth and sand weight processing part 60 of this embodiment, thedisplay control part 66 displays the main screen on the display device40 (Step S701). The display control part 66 may, for example, displaythe main screen on the display device 40 when the engine 11 of theshovel 100 is activated.

Subsequently, the display control part 66 determines whether or not theinput device 42 (switch) corresponding to the loading work screen isselected (Step S702). Specifically, the display control part 66determines whether or not the input device 42 corresponding to the iconimage for guiding the transition to the loading work screen is operated.

In Step S702, in a case where the corresponding input device 42 is notselected, the display control part 66 returns to Step S701.

In Step S702, when the corresponding input device 42 is selected, thedisplay control part 66 transitions the main screen to the loading workscreen. In other words, the display control part 66 displays, on thedisplay device 40, the loading work screen (Step S703). On the loadingwork screen displayed here, the correction icon image corresponding tothe input device 42 for updating the reference value is displayed.

Subsequently, the earth and sand weight processing part 60 causes theweight calculation part 61 to calculate the weight in the bucket 6 (StepS704). The earth and sand weight processing part 60 then causes thereference value correction part 67 to determine whether or not thedifference between the weight of the load calculated in Step S704 andthe reference value is less than or equal to the predetermined thresholdvalue TH1 (Step S705).

In Step S705, in a case where the difference is not less than or equalto the predetermined value, that is, it is the state in which the earthand sand and the like are loaded on the bucket 6, the earth and sandweight processing part 60 returns to Step S704.

In Step S705, when the difference is less than or equal to thepredetermined value, that is, it is the state in which the bucket 6 isin the empty state after dumping the earth and sand, the reference valuecorrection part 67 enables reception of an operation on the input device42 (switch) corresponding to the correction icon image (Step S706).

Specifically, the reference value correction part 67 causes the displaycontrol part 66 to change the display mode of the correction icon image,and allows the input device 42 corresponding to the correction iconimage to be selected.

The earth and sand weight processing part 60 then determines whether ornot the input device 42 (switch) corresponding to the correction iconimage is selected (Step S707). In a case where the corresponding inputdevice 42 is not selected in Step S707, the earth and sand weightprocessing part 60 returns to Step S704.

When the corresponding input device 42 is selected in Step S707, thereference value correction part 67 performs the correction to set theweight of the bucket 6 calculated by the weight calculation part 61 inStep S704 as the reference value (Step S708). Therefore, it can be saidthat the correction icon image of this embodiment is an icon imagecorresponding to an instruction to correct the reference value used inthe calculation of the load weight loaded in the bucket 6.

Subsequently, the earth and sand weight processing part 60 determineswhether or not the loading work is completed (Step S709). Specifically,the earth and sand weight processing part 60 may determine that theloading work is completed when transition from the loading work screento the main screen occurs.

In Step S709, in a case where the loading work has not been completed,the earth and sand weight processing part 60 returns to Step S704. InStep S709, in a case where the loading work has been completed, theearth and sand weight processing part 60 finishes the processing by thereference value correction part 67.

Next, a display example of the display device 40 of this embodiment willbe described. FIG. 8 is a diagram for illustrating an example of themain screen.

A display device 40 illustrated in FIG. 8 includes an image display part41 and an input device 42. The image display part 41 is a screen onwhich various images are displayed, and in FIG. 8 , a main screen isdisplayed on the image display part 41. The input device 42 includesvarious types of menu switches.

First, the image display part 41 will be described. As illustrated inFIG. 8 , the image display part 41 includes a date and time display area41 a, a travel mode display area 41 b, an attachment display area 41 c,a fuel efficiency display area 41 d, an engine control state displayarea 41 e, an engine operating time display area 41 f, a cooling watertemperature display area 41 g, a remaining fuel amount display area 41h, a rotation speed mode display area 41 i, a remaining urea-wateramount display area 41 j, a hydraulic oil temperature display area 41 k,an air conditioner operation state display area 41 m, an image displayarea 41 n, and a menu display area 41 p.

The travel mode display area 41 b, the attachment display area 41 c, theengine control state display area 41 e, the rotation speed mode displayarea 41 i, and the air conditioner operation state display area 41 m areareas for displaying setting state information that is informationrelated to the setting state of the shovel 100. The fuel efficiencydisplay area 41 d, the engine operating time display area 41 f, thecooling water temperature display area 41 g, the remaining fuel amountdisplay area 41 h, the remaining urea-water amount display area 41 j,and the hydraulic oil temperature display area 41 k are areas fordisplaying operation state information that is information related tothe operation state of the shovel 100.

Specifically, the date and time display area 41 a is an area fordisplaying the current date and time. The travel mode display area 41 bis an area for displaying the current travel mode. The attachmentdisplay area 41 c is an area for displaying an image representing thecurrently mounted attachment. The fuel efficiency display area 41 d isan area for displaying fuel efficiency information calculated by thecontroller 30. The fuel efficiency display area 41 d includes an averagefuel efficiency display area 41 d 1 for displaying lifelong average fuelefficiency or section average fuel efficiency, and an instantaneous fuelefficiency display area 41 d 2 for displaying instantaneous fuelefficiency.

The engine control state display area 41 e is an area for displaying thecontrol state of the engine 11. The engine operating time display area41 f is an area for displaying the cumulative operating time of theengine 11. The cooling water temperature display area 41 g is an areafor displaying the current temperature state of the engine coolingwater. The remaining fuel amount display area 41 h is an area fordisplaying a remaining amount state of the fuel stored in the fuel tank.

The rotation speed mode display area 41 i is an area for displaying, asan image, the current rotation speed mode set by an engine rotationspeed adjustment dial 75. The remaining urea-water amount display area41 j is an area for displaying, as an image, the state of the remainingamount of urea-water stored in the urea-water tank. The hydraulic oiltemperature display area 41 k is an area for displaying the temperaturestate of the hydraulic oil in the hydraulic oil tank.

The air conditioner operation state display area 41 m includes an airoutlet display area 41 m 1 for displaying the current position of theair outlet, an operation mode display area 41 m 2 for displaying thecurrent operation mode, a temperature display area 41 m 3 for displayingthe current set temperature, and an air volume display area 41 m 4 fordisplaying the current set air volume.

The image display area 41 n is an area where an image captured by theimaging device S6 is displayed. In the example of FIG. 8 , the imagedisplay area 41 n displays a bird's-eye view image FV and a rear imageCBT. The bird's-eye view image FV is, for example, a virtual viewpointimage generated by the display control part 66, and is generated basedon images captured by the rear camera S6B, the left camera S6L, and theright camera S6R.

Furthermore, a shovel graphic GE corresponding to the shovel 100 isarranged in the central portion of the bird's-eye view image FV. This isto allow the operator to intuitively ascertain the positionalrelationship between the shovel 100 and an object existing around theshovel 100. The rear image CBT is an image illustrating the space behindthe shovel 100 and includes an image GC of the counterweight. The rearimage CBT is a real viewpoint image generated by a controller 40 a basedon an image captured by the rear camera S6B.

The image display area 41 n includes a first image display area 41 n 1located in the upper area and a second image display area 41 n 2 locatedin the lower area therewithin. In the example of FIG. 8 , the bird's-eyeview image FV is arranged in the first image display area 41 n 1, andthe rear image CBT is arranged in the second image display area 41 n 2.In the image display area 41 n, however, the bird's-eye view image FVmay be arranged in the second image display area 41 n 2, and the rearimage CBT may be arranged in the first image display area 41 n 1.

Furthermore, in the example of FIG. 8 , the bird's-eye view image FV andthe rear image CBT are arranged adjacent to each other in the up-downdirection, but may be arranged to be spaced apart from each other. Inthe example of FIG. 8 , the image display area 41 n is a vertically longarea, but the image display area 41 n may be a laterally long area.

When the image display area 41 n is a horizontally long area, in theimage display area 41 n, the bird's-eye view image FV may be arranged onthe left side area as being the first image display area 41 n 1, and therear image CBT may be arranged on the right side area as being thesecond image display area 41 n 2. In such a case, the bird's-eye viewimage FV and the rear image CBT may be arranged to be spaced apart fromeach other in the right-left direction, or the positions of thebird's-eye view image FV and the rear image CBT may be switched.

Furthermore, in this embodiment, an icon image 41 x is displayed in eachof the first image display area 41 n 1 and the second image display area41 n 2. The icon image 41 x is an image representing a relativerelationship between the position of the imaging device S6 and thedirection of the attachment of the upper swing body 3.

The icon image 41 x according to this embodiment includes an image 41 xMof the shovel 100, an image 41 xF indicating the front side of theshovel 100, and an image 41 xB indicating the rear side of the shovel100. The icon image 41 x also includes an image 41 xL indicating theleft side of the shovel 100, an image 41 xR indicating the right side ofthe shovel 100, and an image 41 x 1 indicating the inside of the cabin10.

The images 41 xF, 41 xB, 41 xL, 41 xR, and 41 x 1 correspond to theimages captured by the camera S6F that captures images of the front sideof the shovel 100, the camera S6B that captures images of the rear sideof the shovel 100, the camera S6L that captures images of the left sideof the shovel 100, the camera S6R that captures images of the right sideof the shovel 100, a camera in the cabin respectively.

In this embodiment, when an image corresponding to each camera isselected in the icon image 41 x, the image data captured by the cameracorresponding to the selected image is displayed in the image displayarea 41 n.

In the example of FIG. 8 , in the first image display area 41 n 1, thedisplay mode for the images 41 xB, 41 xL, and 41 xR is different fromthe display mode for the images 41 xF and 41 xI. Therefore, it can beseen that the bird's-eye view image represented by the image datasynthesized from the image data captured by the cameras S6B, S6L, andS6R corresponding to the images 41 xB, 41 xL, and 41 xR, respectively,is displayed in the first image display area 41 n 1.

In the second image display area 41 n 2, the display mode for the image41 xB is different from the display mode for the images 41 xF, 41 xL, 41xR, and 41 xI. Therefore, it can be seen that the image represented bythe image data captured by the camera S6B corresponding to the image 41xB is displayed in the second image display area 41 n 2.

The menu display area 41 p includes tabs 41 p 1 to 41 p 7. In theexample of FIG. 8 , the tabs 41 p 1 to 41 p 7 are arranged at thelowermost portion of the image display part 41 so as to be spaced apartfrom each other in the left-right direction. Icon images for displayingvarious kinds of information are displayed in the tabs 41 p 1 to 41 p 7.

In the tab 41 p 1, a menu detail item icon image for displaying menudetail items is displayed. When the tab 41 p 1 is selected by theoperator, the icon images displayed in the tabs 41 p 2 to 41 p 7 areswitched to icon images related to the menu detailed items.

In the tab 41 p 4, an icon image for displaying information related tothe digital level is displayed. When the tab 41 p 4 is selected by theoperator, the rear image CBT is switched to a screen indicatinginformation related to the digital level. However, a screen indicatinginformation related to the digital level may be displayed by beingsuperimposed on the rear image CBT or by reducing the size of the rearimage CBT.

Furthermore, the bird's-eye view image FV may be switched to the screenindicating information related to the digital level, or the screenindicating information related to the digital level may be displayed bybeing superimposed on the bird's-eye view image FV or by reducing thesize of the bird's-eye view image FV.

In the tab 41 p 5, an icon image for transitioning the main screendisplayed on the image display part 41 to the loading work screen isdisplayed. When the operator selects the described-below input device 42corresponding to the tab 41 p 5, the main screen displayed on the imagedisplay part 41 transitions to a loading work screen. At this time, theimage display area 41 n is continuously displayed, and the menu displayarea 41 p is switched to an area for displaying information related tothe loading work.

In the tab 41 p 6, an icon image for displaying information related tocomputerized construction is displayed. When the tab 41 p 6 is selectedby the operator, the rear image CBT is switched to a screen illustratinginformation related to the computerized construction. However, thescreen indicating the information related to the computerizedconstruction may be displayed by being superimposed on the rear imageCBT or by reducing the size of the rear image CBT. Furthermore, thebird's-eye view image FV may be switched to the screen indicatinginformation related to the computerized construction, or the screenindicating information related to the digital level by beingsuperimposed on the bird's-eye view image FV or by reducing the size ofthe bird's-eye view image FV.

In the tab 41 p 7, an icon image for displaying information related tothe crane mode is displayed. When the tab 41 p 7 is selected by theoperator, the rear image CBT is switched to a screen illustratinginformation on the crane mode. However, the screen indicatinginformation related to the crane mode may be displayed by beingsuperimposed on the rear image CBT or by reducing the size of the rearimage CBT. Furthermore, the bird's-eye view image FV may be switched tothe screen indicating information related to the crane mode, or thescreen indicating information related to the crane mode may be displayedby being superimposed on the bird's-eye view image FV or by reducing thesize of the bird's-eye view image FV.

No icon image is displayed on the tabs 41 p 2 and 41 p 3. Therefore,even when the operator operates the tabs 41 p 2 and 41 p 3, no changeoccurs in the image displayed on the image display part 41.

The icon images displayed on the tabs 41 p 1 to 41 p 7 are not limitedto the above-described examples, and icon images for displaying otherinformation may be displayed.

Next, the input device 42 will be described. As illustrated in FIG. 8 ,the input device 42 is configured by one or more of button-type switcheson which selection, setting input, and the like of the tabs 41 p 1 to 41p 7 are performed by the operator.

In the example of FIG. 8 , the input device 42 includes seven switches42 a 1 to 42 a 7 arranged in the upper area and seven switches 42 b 1 to42 b 7 arranged in the lower area, within the area for the input device.The switches 42 b 1 to 42 b 7 are arranged below the switches 42 a 1 to42 a 7, respectively.

The number, form, and arrangement of the switches of the input device 42are, however, not limited to the above-described example. For example,the functions of the button-type switches may be integrated into one bya jog wheel, a jog switch, or the like, or the input device 42 may beseparated from the display device 40.

Alternatively, the tabs 41 p 1 to 41 p 7 may be arranged on a touchpanel in which the image display part 41 and the input device 42 areintegrated, and directly operated.

The switches 42 a 1 to 42 a 7 are arranged below the tabs 41 p 1 to 41 p7 so as to correspond to the tabs 41 p 1 to 41 p 7, respectively, andfunction as switches that select the tabs 41 p 1 to 41 p 7,respectively.

Since the switches 42 a 1 to 42 a 7 are arranged below the tabs 41 p 1to 41 p 7 so as to correspond to the tabs 41 p 1 to 41 p 7, the operatorcan intuitively select the tabs 41 p 1 to 41 p 7.

In FIG. 8 , for example, when the switch 42 a 1 is operated, the tab 41p 1 is selected, the menu display area 41 p is changed from the one-rowdisplay to the two-row display, and the icon images corresponding to thefirst menu are displayed in the tabs 41 p 2 to 41 p 7. Furthermore, thesize of the rear image CBT is reduced in response to the change of themenu display area 41 p from the one-row display to the two-row display.At this time, since the size of the bird's-eye view image FV ismaintained without being changed, the visibility when the operatorchecks the surroundings of the shovel 100 does not deteriorate.

When the switch 42 a 5 is operated, the display control part 66determines that the tab 41 p 5 is selected, and transition from the mainscreen to the loading work screen illustrated in FIG. 8 occurs.

Specifically, when the switch 42 a 5 is operated, the display controlpart 66, while maintaining the image display area 41 n, sets the menudisplay area 41 p as a work information display area for displayinginformation related to the loading work.

As described above, in this embodiment, since the captured image iscontinuously displayed in the image display area 41 n also on theloading work screen, the visibility when the operator checks theperiphery of the shovel 100 is not deteriorated.

The switch 42 b 1 is a switch for switching the captured image displayedin the image display area 41 n. Each time the switch 42 b 1 is operated,the captured image displayed in the first image display area 41 n 1 ofthe image display area 41 n is switched among, for example, the rearimage, the left image, the right image, and the bird's-eye view image.

Each time the switch 42 b 1 is operated, the captured image displayed inthe second image display area 41 n 2 of the image display area 41 n maybe switched among, for example, the rear image, the left image, theright image, and the bird's-eye view image.

The display control part 66 may change the display mode for the images41 xF, 41 xB, 41 xL, 41 xR, and 41 x 1 in the icon image 41 x accordingto the operation of the switch 42 b 1.

Furthermore, each time the switch 42 b 1 is operated, in the imagedisplay area 41 n, the captured image displayed in the first imagedisplay area 41 n 1 and the captured image displayed in the second imagedisplay area 41 n 2 may be switched.

As described above, the switch 42 b 1 as the input device 42 may switcheither one of the screens displayed in the first image display area 41 n1 and the second image display area 41 n 2, or may switch both thescreen displayed in the first image display area 41 n 1 and the secondimage display area 41 n 2. Furthermore, a switch for switching thescreen displayed in the second image display area 41 n 2 may beseparately provided.

The switches 42 b 2 and 42 b 3 are switches for adjusting the air volumeof the air conditioner. In the example illustrated in FIG. 8 , when theswitch 42 b 2 is operated, the air volume of the air conditionerdecreases, and when the switch 42 b 3 is operated, the air volume of theair conditioner increases.

The switch 42 b 4 switches between ON and OFF of the cooling and heatingfunctions. In the example of FIG. 8, when the cooling the switch 42 b 4is operated, the cooling and heating functions are switched between ONand OFF.

The switches 42 b 5 and 42 b 6 are switches for adjusting the settemperature of the air conditioner. In the example of FIG. 8 , thesetting temperature is lowered when the switch 42 b 5 is operated, andthe setting temperature is raised when the switch 42 b 6 is operated.

The switch 42 b 7 is a switch capable of switching the display of theengine operating time display area 41 f.

The switches 42 a 2 to 42 a 6 and 42 b 2 to 42 b 6 are configured to beable to input numbers displayed on or near the respective switches. Theswitches 42 a 3, 42 a 4, 42 a 5, and 42 b 4 are configured to move thecursor left, up, right, and down, respectively, when the cursor isdisplayed on the menu screen.

Note that the functions provided to the switches 42 a 1 to 42 a 7 and 42b 1 to 42 b 7 are examples, and the switches may be configured to beable to execute other functions.

As described above, when the tab 41 p 1 is selected in a state where thebird's-eye view image FV and the rear image CBT are displayed in theimage display area 41 n, the first menu detailed items are displayed inthe tabs 41 p 2 to 41 p 7 in the state where the bird's-eye view imageFV and the rear image CBT are displayed. Therefore, the operator canascertain the first menu detailed items while ascertaining thebird's-eye view image FV and the rear image CBT.

Furthermore, the bird's-eye view image FV is displayed in the imagedisplay area 41 n without changing the size thereof before and after thetab 41 p 1 is selected. The visibility when the operator checks thesurroundings of the shovel 100 does not deteriorate.

Hereinafter, the loading work screen of this embodiment will bedescribed with reference to FIG. 9 . FIG. 9 is a diagram forillustrating an example of the loading work screen. The loading workscreen in FIG. 9 is displayed on the display device 40 in Step S703 ofFIG. 7 , for example. The loading work screen illustrated in FIG. 9 is ascreen capable of transitioning to a screen for performing varioussettings in the loading work, in other words, is a home screen of theloading work.

In the example of FIG. 9 , the loading work screen is displayed on theimage display part 41. The image display part 41 includes the imagedisplay area 41 n and a work information display area 43 n.

In the work information display area 43 n, a load amount image 43 a, aremaining load amount 43 b, a loaded amount 43 c, an icon image 43 d ofthe bucket 6, and a bucket 6's earth and sand weight 43 e are displayed.Icon images 44 a 1 to 44 a 7 are also displayed in the work informationdisplay area 43 n.

The load amount image 43 a includes an image of a side surface of thedump truck and a bar chart image indicating the loaded amount on thecargo bed of the dump truck. The bar chart image indicates the ratio ofthe amount of the earth and sand loaded on the cargo bed of the dumptruck to the maximum load amount of the dump truck.

Furthermore, the bar chart image included in the load amount image 43 aof this embodiment is provided with scale marks, and is displayed suchthat as the ratio of the loaded amount to the maximum load amountincreases, the range of the ratio assigned to the interval between thescale marks is decreased.

Therefore, in this embodiment, as the ratio of the loaded amount to themaximum load amount increases, the change in the loaded amount isdisplayed in more detail.

The remaining load amount 43 b is a numerical value indicating adifference between the maximum load amount and the current loadedamount. In other words, the remaining load amount 43 b is the remainingweight of the earth and sand that can be loaded on the dump truck.

The loaded amount 43 c is a numerical value indicating the amount of theload loaded on the cargo bed of the dump truck.

The icon image 43 d is an image including an image 43 d 1 of the load inthe bucket 6, and represents the presence or absence of the load in thebucket 6. In the example of FIG. 9 , the icon image 43 d includes theimage 43 d 1, and it can be seen that the bucket 6 is loaded with a loadin a state before dumping.

Furthermore, when the load (earth and sand) in the bucket 6 is dumpedonto the cargo bed of the dump truck, the icon image 43 d may be animage of only the bucket 6 not including the image 43 d 1. The displaycontrol part 66 may change the shape of the image 43 d 1 according tothe weight of the load in the bucket 6.

The bucket 6's earth and sand weight 43 e is a numerical valueindicating the weight of the load in the bucket 6. That is, the weight43 e is the weight of the earth and sand to be dumped onto the dumptruck.

For example, in a case where the weight 43 e is larger than theremaining load amount 43 b, that is, in a case where dumping earth andsand loaded onto the bucket 6 results in overloading, the displaycontrol part 66 of this embodiment may change the display mode for theload amount image 43 a, the remaining load amount 43 b, the loadedamount 43 c, and the like. Specifically, the display control part 66 mayset the display color of the load amount image 43 a, the remaining loadamount 43 b, the loaded amount 43 c, and the like to red or the like.

In a case where overloading does not occur even if earth and sand loadedonto the bucket 6 is dumped, the display control part 66 may set thebackground color of the load amount image 43 a, the remaining loadamount 43 b, the loaded amount 43 c, and the like to green or the like.

Furthermore, when the load on the cargo bed of the dump truck exceedsthe maximum load, the display control part 66 may cause the displaydevice 40 to display information for instructing the operator to scoopearth and sand out from the cargo bed.

Each of the icon images 44 a 1 to 44 a 7 is an icon image for displayingvarious input fields and the like in the work information display area43 n. The icon images 44 a 1 to 44 a 7 may be displayed so as tocorrespond to the switches 42 a 1 to 42 a 7, respectively.

For example, when the switch 42 a 1 corresponding to the icon image 44 a1 is operated, the display control part 66 may transition the display ofthe image display part 41 from the loading work screen to the mainscreen. Also, when the switch 42 a 2 corresponding to the icon image 44a 2 is operated, the display control part 66 may display various settingscreens in the work information display area 43 n.

Furthermore, when the switch 42 a 3 corresponding to the icon image 44 a3 is operated, the display control part 66 may display the input fieldof the target value of the load amount in the loading work in the workinformation display area 43 n.

The icon image 44 a 5 is the correcting icon image for the referencevalue and corresponds to the switch 42 a 5. When the switch 42 a 5 isselected on the loading work screen, the reference value correction part67 of this embodiment corrects the reference value used to calculate theweight of the load on the bucket 6. In other words, when the switch 42 a5 is selected, the reference value correction part 67 performs theprocessing of Step S708 in FIG. 7 .

As described above, in this embodiment, on the home screen of theloading operation, the image data captured by the imaging device S6 andthe correction icon image corresponding to the switch corresponding tothe correction of the reference value in the calculation of the weightof the load in the bucket 6 are displayed together.

Furthermore, in this embodiment, only in a case where it is determinedthat the bucket 6 is in the empty state, the display mode of thecorrection icon image is changed, and the operator is notified of thetiming for correcting the reference value.

Specifically, the icon image 44 a 5 may be grayed out in a case where itis not determined that the bucket 6 is in the empty state, that is, acase where it is determined that the bucket 6 is in the state afterexcavation (before dumping). Note that, in such a case, the display modeof the icon image 44 a 5 is not limited to the gray-out display, and anydisplay mode is acceptable as long as the display mode is different fromthe display mode of the icon image indicating that the selection of thecorresponding switch is valid among the other icon images 44 a 1 to 44 a7.

Furthermore, in a case where it is determined that the bucket 6 is inthe empty state, the icon image 44 a 5 is changed from the gray-outdisplay to the display mode indicating that the selection of the switch42 a 5 is valid. Specifically, the icon image 44 a 5 may be displayed asa color image, or may be displayed in the same display mode as thedisplay mode of the icon image indicating that the selection of thecorresponding switch is valid among the icon images 44 a 1 to 44 a 7.

As described above, in this embodiment, the icon image 44 a 5(correction icon image) corresponding to the switch 42 a 5 forinstructing the correction of the reference value used for calculationof the weight of the load on the bucket 6 is displayed together with theimage data acquired by the imaging device S6 on the home screen of theloading work.

Furthermore, in this embodiment, in a case where it is determined thatthe bucket 6 is in the empty state, the display mode of the correctionicon image 44 a 5 is changed. Then, the operator of the shovel 100 isnotified that it is time to correct the reference value.

When the display mode of the correction icon image 44 a 5 is changed,the operator can correct the reference value only by selecting theswitch 42 a 5. In other words, when the display mode of the correctionicon image 44 a 5 is changed, the operator can set the weight of thebucket 6 in the empty load state only by selecting the switch 42 a 5.Therefore, according to this embodiment, the weight of the endattachment in the empty load state can be set.

Note that the timing at which the reference value is corrected may benotified to the operator by a method other than the method of changingthe display mode of the correction icon image 44 a 5. For example, thetiming at which the correction of the reference value is performed maybe notified by voice, or may be notified by displaying a messageprompting the correction of the reference value, or the like. In such acase, the display device 40 may include, for example, an output partthat outputs a notification indicating that it is time to correct thereference value by a method other than display.

Furthermore, for example, although the controller 30 is mounted on theshovel 100 in the above-described embodiment, the controller 30 may beinstalled outside the shovel 100. In such a case, the controller 30 maybe, for example, a control device installed in a remote control room.The display device 40 may also be installed in the remote control room.The display device 40 may then be connected to the control deviceinstalled in the remote control room. The control device installed inthe remote control room may receive output signals from various sensorsattached to the shovel 100, calculate the weight of the load, anddetermine the timing for correcting the reference value used forcalculation of the weight of the load. Furthermore, for example, in theabove-described embodiment, the display device 40 may function as adisplay part in the assist device 200. In such a case, the assist device200 may be connected to the controller 30 of the shovel 100 or thecontrol device installed in the remote control room.

In each of the above-described embodiments, the shovel 100 including thebucket as the end attachment has been described as an example. It is,however, not limited to the shovel 100 including the bucket. The shovelof the present disclosure also includes a work machine provided with agrapple, a lifting magnet, or the like as an end attachment at the tipof an attachment.

This embodiment has been described above with reference to specificexamples. However, the present disclosure is not limited to thesespecific examples. Modifications to these specific examples by thoseskilled in the art are also included in the scope of the presentdisclosure as long as they include the features of the presentdisclosure. Each element included in each specific example describedabove and the arrangement, condition, shape, and the like thereof arenot limited to those illustrated and can be appropriately changed. Theelements included in the specific examples described above may beappropriately combined as long as no technical contradiction occurs.

What is claimed is:
 1. A display device for a shovel, wherein: the display device is configured to display a screen that includes an image represented by image data captured by an imaging device included in the shovel; and an icon image corresponding to an instruction to correct a reference value used to calculate a weight of a load object conveyed by an end attachment of the shovel.
 2. The display device according to claim 1, wherein a display mode of the icon image is changed to a display mode indicating that an operation of correcting the reference value is permitted, when a state of the end attachment satisfies a predetermined condition.
 3. The display device according to claim 2, wherein the display mode of the icon image is displayed in a display mode indicating that the operation of correcting the reference value is invalid, when the state of the end attachment does not satisfy the predetermined condition.
 4. The display device according to claim 3, wherein the predetermined condition is that the state of the end attachment is determined to be an empty load state.
 5. The display device according to claim 4, wherein the predetermined condition is that a difference between a weight of the end attachment and the reference value is less than or equal to a predetermined threshold value.
 6. The display device according to claim 5, wherein an operation of setting the reference value is an operation of selecting an input device associated with the icon image, and when the operation is performed, the weight of the end attachment when the predetermined condition is satisfied is set as the reference value.
 7. The display device according to claim 6, wherein the screen is displayed in loading of the load object onto a cargo bed of a conveying vehicle from the end attachment.
 8. The display device according to claim 7, wherein the display device is configured to display another screen, said another screen including the image data captured by the imaging device and an icon image for displaying the screen, and said another screen transitions to the screen when an input device corresponding to the icon image for displaying the screen is selected.
 9. The display device for the shovel according to claim 8, wherein the screen is a loading work screen, said another screen is a main screen, the icon image for displaying the screen is an icon image for transitioning the main screen to the loading work screen, and the input device corresponding to the icon image for displaying the screen is an input device corresponding to a tab displaying the icon image for transitioning the main screen to the loading work screen.
 10. The display device for the shovel according to claim 1, wherein the screen includes an image display area displaying the image data captured by the imaging device and a work information display area displaying information on loading work.
 11. The display device according to claim 10, wherein a load amount image, a remaining load amount, a loaded amount, an icon image of the end attachment, and a weight of earth and sand in the end attachment are displayed in the work information display area.
 12. The display device according to claim 11, wherein the load amount image includes an image of a side surface of a dump truck, and a bar chart image indicating a loaded amount on a cargo bed of the dump truck, and the bar chart image indicates a ratio of the loaded amount of earth and sand on the cargo bed of the dump truck to a maximum load amount of the dump truck.
 13. A shovel comprising: an upper swing body; a lower traveling body; an end attachment; a hardware processor configured to calculate a weight of a load object conveyed by the end attachment; and a display device configured to display an icon image corresponding to an instruction to correct a reference value used to calculate the weight of the load object conveyed by the end attachment, wherein the hardware processor is configured to change a display mode of the icon image upon determining a timing of correction of the reference value used to calculate the weight of the load object. 